Class 9 Maths Chapter 5 End of Chapter Exercises Solutions Ganita Manjari 2026

Class 9 Maths Chapter 5 End of Chapter Exercises Solutions | Ganita Manjari 2026

📘 NCERT Ganita Manjari (2026) 📚 CBSE 2026–27 🏆 Complete 26 Questions

Class 9 Maths Chapter 5 End-of-Chapter Exercises Solutions

Ganita Manjari 2026 • Complete Chapter 5 Revision

Prepare with complete Class 9 Maths Chapter 5 End of Chapter Exercises Solutions from the latest NCERT Ganita Manjari (2026). All 26 end-of-chapter questions are presented in textbook order with clear, student-friendly, step-by-step solutions for homework, self-study, revision and CBSE examination preparation.

📖
Chapter
5
❓
End Questions
26 Questions
📐
Coverage
Complete
Chapter 5
🎯
Focus
Circles &
Theorems
📝
Solutions
Step-by-Step
⭐
Practice Level
Mixed
🏆
Revision Value
★★★★★
🎯 By the End of These Exercises, You Will Be Able To…
✅ Revise the Major Concepts of Chapter 5
✅ Solve Chord and Distance Problems
✅ Apply Angle and Arc Theorems
✅ Solve Cyclic Quadrilateral Problems
✅ Handle Proof-Based and Application Questions
✅ Complete All 26 End-of-Chapter Questions

📑 Table of Contents

📖 About Class 9 Maths Chapter 5 End-of-Chapter Exercises

Class 9 Maths Chapter 5 End of Chapter Exercises Solutions provide complete, question-wise support for the final exercises of Chapter 5 – I’m Up and Down, and Round and Round from the latest NCERT Ganita Manjari (2026). This page is designed for students who want reliable and easy-to-follow solutions to the End-of-Chapter Exercises in one place.

The complete exercise is presented in the same order as the textbook, with all 26 questions organised clearly for quick access. The page is useful for classroom practice, homework, self-study, revision, doubt-solving, and CBSE examination preparation. Students can use the question navigator to move directly to the question they want to study.

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  • Complete coverage of the Chapter 5 End-of-Chapter Exercises.
  • Question-wise solutions for all 26 questions.
  • Clear presentation following the textbook order.
📚 Page Includes
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🏆 Best For
  • Students following Ganita Manjari (2026).
  • Homework, classroom practice and self-study.
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⭐ Why Use This Page?
  • One place for the complete end exercise.
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🔎 Jump to Any Question

Quickly jump to any question from the 26 End-of-Chapter Exercises of Class 9 Maths Chapter 5.

Regular Question ★ Higher-Order Question

📚 Learn Before You Solve

✨ Understand the ideas first — then solve with confidence

Before solving the End-of-Chapter Exercise — Chapter 5: Circles, revise the essential circle concepts and theorems you need.

This LBWS focuses only on the new and important ideas required here. Concepts already explained in earlier exercises are linked instead of being repeated.

Theorem 10
Equal Angles → Concyclic Points
Theorem Statement
If a line segment AB joining two points A and B subtends equal angles at two other points C and D that lie on the same side of AB, then the four points lie on a circle.
Given:
Consider segment AB. Points C and D lie on the same side of AB; points C and D are not on the line AB; and ∠ACB = ∠ADB.
To show:
A, B, C and D lie on the same circle.
Fig. 5.27A — D outside the circle
Fig. 5.27A — Theorem 10: Equal Angles and Concyclic Points Class 9 Mathematics circle diagram based on Ganita Manjari. A, B and C lie on a circle. D is outside the circle and line AD meets the circle again at E. Points A, E and D are collinear. The diagram illustrates the configuration used in the proof of Theorem 10 concerning equal angles and concyclic points. A B C E D
Fig. 5.27A — D outside the circle; AD meets the circle again at E
D is assumed to be outside the circle through A, B and C.
Fig. 5.27B — D inside the circle
Fig. 5.27B — Theorem 10: D inside the circle Class 9 Mathematics diagram based on Ganita Manjari. A, B and C lie on a circle. Point D lies inside the circle. Line AD is extended to meet the circle again at E. Points A, D and E are collinear. Lines AB, AC, CB, BE and BD form the configuration used in the proof of Theorem 10. A B C D E
Fig. 5.27B — D lies inside the circle and AD meets the circle again at E
D is assumed to be inside the circle through A, B and C.
💡 Why are two figures needed?
If D is not on the circle, it must be either outside or inside the circle. NCERT eliminates both possibilities.
✍️ Proof
1
Construct the circle through A, B and C
The points A, B and C are non-collinear points.
So, using Theorem 1, there is a circle passing through A, B and C.

Let us show that D also lies on this circle.
2
Assume D is not on the circle
Suppose D is not on the circle. Then D is either inside or outside the circle.
Join AD.
Case 1 — D is outside the circle
If D is outside the circle, then AD intersects the circle again at E, as shown in Fig. 5.27A.

Now C and E are on the same segment of the arc formed by chord AB. Therefore,
∠ACB = ∠AEB
Angles in the same segment of a circle

Since ∠AEB is an exterior angle of triangle BED,
∠AEB > ∠ADB
Therefore,
∠ACB > ∠ADB
But this contradicts the given condition
∠ACB = ∠ADB
Case 2 — D is inside the circle
If D is inside the circle, extend AD to meet the circle at E, as shown in Fig. 5.27B.

Again, C and E are on the same segment of the arc formed by chord AB. Therefore,
∠ACB = ∠AEB
Angles in the same segment of a circle

Since ∠ADB is an exterior angle of triangle BED,
∠ADB > ∠AEB
Therefore,
∠ADB > ∠ACB
But this contradicts the given condition
∠ACB = ∠ADB
🔍 Both possibilities are impossible
D cannot be outside the circle and D cannot be inside the circle.

Therefore, D must be on the circle passing through A, B and C.
✅ Hence Proved
A, B, C and D are concyclic.
🧠 Remember
Equal angles subtended by the same line segment at two points on the same side → the four points are concyclic.

Cyclic Quadrilateral

A four-sided figure whose vertices lie on the same circle.

Once four points are known to lie on the same circle, they form a special type of quadrilateral called a cyclic quadrilateral.
📐 Cyclic Quadrilateral ABCD
Cyclic quadrilateral ABCD A circle containing four points A, B, C and D on its circumference. Joining the four points forms cyclic quadrilateral ABCD. A B C D O
The four vertices A, B, C and D lie on the same circle.
What is a Cyclic Quadrilateral?
A quadrilateral whose four vertices lie on the same circle is called a cyclic quadrilateral.

In the figure, the four vertices A, B, C and D all lie on the circumference of the same circle.
🎯 The Key Condition
The important point is not merely that ABCD is a quadrilateral.
Its four vertices must lie on one common circle.
🔗 Connection with Concyclic Points
If four points are concyclic, joining them in order forms a cyclic quadrilateral.

So:
Concyclic vertices → Cyclic quadrilateral
🧠 Remember
Four vertices on one circle → Cyclic quadrilateral
Theorem 11
Opposite Angles of a Cyclic Quadrilateral
Theorem Statement
The sum of two opposite angles of a cyclic quadrilateral is 180°.
Given:
A, B, C and D are the vertices of a cyclic 4-gon (Fig. 5.28). The circle has centre O.
To show:
∠BAD + ∠BCD = 180°
Figure 5.28 — Cyclic quadrilateral ABCD with centre O
Fig. 5.28 — Cyclic quadrilateral ABCD with centre O
💡 Key Idea
Each angle at the circumference is half the angle subtended by the corresponding arc at the centre.
✍️ Proof
Consider arc BCD. Point A is on the circle and lies outside the arc BCD.

So, ∠BAD subtends at the centre O the reflex angle BOD.
∠BAD = ½ × reflex angle BOD
To move from OB to OD along C gives the reflex angle BOD.

Similarly, ∠BCD is half the angle subtended by the arc BAD at the centre O.
∠BCD = ½ × ∠BOD
The reflex angle BOD and the remaining angle BOD together make one complete angle at the centre O.
reflex angle BOD + ∠BOD = 360°
Therefore,
∠BAD + ∠BCD = ½ × 360°
Hence,
∠BAD + ∠BCD = 180°
✅ Hence Proved
∠BAD + ∠BCD = 180°
🧠 Remember
In a cyclic quadrilateral, opposite angles are supplementary.
Opposite angles → 180°
Theorem 12
Converse of Theorem 11 — Cyclic Quadrilateral
Theorem Statement
If two opposite angles of a quadrilateral add up to 180°, then the vertices of the quadrilateral lie on a circle, i.e., they are concyclic.
Given:
ABCD is a 4-gon.
∠BAD + ∠BCD = 180°.
∠ABC + ∠CDA = 180°.
To show:
ABCD is cyclic.
📐 Figure 5.29 — C outside the circle
Figure 5.29 showing quadrilateral ABCD with C outside the circle through A, B and D
Fig. 5.29 — Circle through A, B and D; CD meets the circle again at E
📐 Figure 5.29B — C inside the circle
Figure showing quadrilateral ABCD with C inside the circle through A, B and D
C lies inside the circle through A, B and D; CD meets the circle again at E.
💡 Why two cases?
If C does not lie on the circle through A, B and D, then C must be either outside or inside the circle.

We eliminate both possibilities.
✍️ Proof
Suppose ABCD is not cyclic.

Since A, D and B are non-collinear, there is a circle passing through A, D and B.

If this circle does not pass through C, there are two cases:
C is outside the circle or C is inside the circle.
Case 1 — C is outside the circle
Let E be the point where CD meets the circle again.

Then ABED is a cyclic 4-gon.

So, from Theorem 11,
∠BAD + ∠BED = 180°
We are also given
∠BAD + ∠BCD = 180°
Therefore,
∠BCD = ∠BED
But ∠BED is the exterior angle of triangle BEC.

Therefore, by the exterior angle property,
∠BED > ∠BCE
Since B, C, D are arranged as shown in the figure,
∠BCE = ∠BCD
Hence,
∠BED > ∠BCD
But we already obtained
∠BED = ∠BCD
This is impossible.
Case 2 — C is inside the circle
Now suppose C lies inside the circle.

Extend CD to meet the circle again at E.

Then ABED is a cyclic 4-gon.

Therefore, by Theorem 11,
∠BAD + ∠BED = 180°
We are given
∠BAD + ∠BCD = 180°
Hence,
∠BED = ∠BCD
Since D, C and E are collinear, the rays ED and EC are in the same direction. Therefore,
∠BED = ∠BEC
Hence,
∠BEC = ∠BCD
Now, since CD and CE are opposite rays,
∠BCD + ∠BCE = 180°
Therefore,
∠BEC + ∠BCE = 180°
But in triangle BCE,
∠BEC + ∠BCE + ∠CBE = 180°
Comparing the two equations,
∠CBE = 0°
This is impossible because B, C and E are not collinear. Therefore, C cannot be inside the circle.
🔍 Both possibilities are impossible
C cannot be outside the circle.
C cannot be inside the circle.

Therefore, our assumption that ABCD is not cyclic is impossible.

Hence, C must lie on the circle passing through A, B and D.
✅ Hence Proved
A, B, C and D are concyclic.
🧠 Remember
If the opposite angles of a quadrilateral add up to 180°,
→ the quadrilateral is cyclic.
This is the converse of Theorem 11.

Cyclicity Test

Use the opposite-angle condition to recognise a cyclic quadrilateral.

Cyclic Quadrilateral
If A, B, C and D lie on the same circle,
opposite angles are supplementary.
Theorem 11
⇄
Opposite Angles
If
∠A + ∠C = 180°
then the four vertices are concyclic.
Theorem 12
🔍 Quick Cyclicity Test
To test whether four points form a cyclic quadrilateral, check whether a pair of opposite angles adds up to 180°.
🧠 Remember
Cyclic → Opposite angles = 180°    ⇄    Opposite angles = 180° → Cyclic

⚡ Quick Revision Dashboard

Chapter 5 — Circles | End-of-Chapter Exercise
🎯 CORE IDEA
Equal Angles ↔ Concyclic Points   |   Opposite Angles ↔ 180°
🔵 1. Concyclic Points
Points are called concyclic when they all lie on the same circle.

Three non-collinear points determine one unique circle. A fourth point is concyclic with them when it also lies on that circle.
Same circle → Concyclic points
⭐ Theorem 10 — Equal Angles → Concyclic
If a line segment AB subtends equal angles at two points C and D on the same side of AB, then A, B, C and D lie on a circle.
∠ACB = ∠ADB
⇒ A, B, C, D are concyclic
🔷 3. Cyclic Quadrilateral
A quadrilateral whose four vertices lie on the same circle is called a cyclic quadrilateral.

Therefore, whenever four points are shown on one circle, the quadrilateral formed by them is cyclic.
4 vertices
→
Same circle
→
Cyclic quadrilateral
⭐ Theorem 11 — Opposite Angles
In a cyclic quadrilateral, the sum of two opposite angles is 180°.
∠BAD + ∠BCD = 180°

∠ABC + ∠ADC = 180°
⭐ Theorem 12 — Converse of Theorem 11
If a pair of opposite angles of a quadrilateral has sum 180°, then the quadrilateral is cyclic.
Opposite angles = 180°
⇒ Quadrilateral is cyclic
🧠 6. Cyclicity Test
To test whether four points form a cyclic quadrilateral, look for either of the two key conditions:
Equal subtended angles
OR
Opposite angles sum to 180°
Either valid condition → Concyclicity
🔗 Theorem Connection
Equal Angles
→
Concyclic Points
→
Cyclic Quadrilateral
→
Opposite Angles = 180°
🔄 Forward + Converse
Cyclic
→
Opposite angles = 180°
Opposite angles = 180°
→
Cyclic
Theorem 11 → forward direction
Theorem 12 → converse direction
⚠️ Don’t Mix the Conditions
Check before applying a theorem
  • Equal angles must subtend the same line segment AB.
  • For Theorem 10, the relevant points lie on the same side of AB.
  • For Theorem 11, the quadrilateral is already known to be cyclic.
  • For Theorem 12, the opposite angles summing to 180° establish cyclicity.
🚦 Quick Decision Test
Ask this first:
Do I know the four points are on one circle?
→ Use cyclic quadrilateral properties.

Do I know equal angles subtending AB?
→ Think Theorem 10.

Do opposite angles add to 180°?
→ Think Theorem 12.
✅ Last-Minute Exam Checklist
✓ Identify the four relevant points.
✓ Check whether they are concyclic.
✓ Look for equal subtended angles.
✓ Check the same-side condition for Theorem 10.
✓ Remember opposite angles = 180°.
✓ Use Theorem 12 for the converse.
⭐ Equal Angles → Concyclic   |   Cyclic → Opposite Angles = 180°   |   Opposite Angles = 180° → Cyclic

📝 Class 9 Maths Chapter 5 End of Chapter Exercises Solutions

Get complete Class 9 Maths Chapter 5 End of Chapter Exercises Solutions based on the latest NCERT Ganita Manjari (2026). Here you can find step-by-step solutions for all 26 end-of-chapter questions from Chapter 5 – I’m Up and Down, and Round and Round, presented in a clear and student-friendly format for self-study, homework, revision and CBSE examination preparation.

📝 26 NCERT Questions 🎯 CBSE Aligned 📘 Ganita Manjari 2026 ⭐ Step-by-Step Solutions

Class 9 Maths Chapter 5 End Exercise Question 1 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 1: Finding the Length of a Chord
In a circle, a chord is 5 cm away from the centre. If the radius of the circle is 13 cm, what is the length of the chord?
✍️ Solution
Given,
Perpendicular distance of the chord from the centre = 5 cm
Radius of the circle = 13 cm
To find,
Length of the chord
📐 Figure
Chord AB at a distance of 5 cm from the centre O A circle with centre O and radius 13 cm. Chord AB is below the centre O. OM is perpendicular to AB and measures 5 cm. M is the midpoint of AB. AM and MB are each 12 cm. A B O M 13 cm 5 cm 12 cm 12 cm AB = ?
OM ⟂ AB,   OM = 5 cm,   OA = 13 cm
✍️ Solution
Let AB be the chord of the circle and O be its centre. Draw OM ⟂ AB, where M lies on the chord AB.
Since the perpendicular from the centre of a circle to a chord bisects the chord,
AM = MB
Therefore, M is the midpoint of AB and AM is half the length of the chord.
In right-angled △OMA,
OA = 13 cm,    OM = 5 cm
By the Baudhāyana–Pythagoras theorem,
OA² = OM² + AM²
13² = 5² + AM²
169 = 25 + AM²
AM² = 144
AM = 12 cm
Hence, the length of the complete chord AB is
AB = AM + MB
AB = 12 + 12 = 24 cm
✅ Final Answer
Length of the chord = 24 cm

Class 9 Maths Chapter 5 End Exercise Question 2 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 2: Angle Subtended by an Arc
An arc of a circle subtends an angle of 70° at the centre. What is the measure of the angle subtended by the arc at a point on the circle?
✍️ Solution
Given,
Angle subtended by the arc at the centre = 70°
To find,
Angle subtended by the same arc at a point on the circle
📐 Figure
Angle subtended by an arc at the centre and at a point on the circle A circle with centre O. Points A and B lie on the circle. Point C lies on the remaining part of the circle. The central angle AOB is 70 degrees and the angle ACB subtended by the same arc is half of the central angle. 70° 35° A B O C
Central angle = 70°; angle subtended at C = 35°
✍️ Solution
Let the arc be AB and let C be a point on the remaining part of the circle.
By Theorem 9 , the angle subtended by an arc at the centre of a circle is twice the angle subtended by the same arc at a point on the remaining part of the circle.
∠AOB = 2 × ∠ACB
Given,
∠AOB = 70°
70° = 2 × ∠ACB
∠ACB = 70° ÷ 2
∠ACB = 35°
✅ Final Answer
Angle subtended by the arc at the point on the circle = 35°

Class 9 Maths Chapter 5 End Exercise Question 3 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 3: Distance of a Chord from the Centre
The diameter of a circle is 26 cm. A chord of length 24 cm is drawn in the circle. Find the distance from the centre of the circle to the chord.
✍️ Solution
Given,
Diameter of the circle = 26 cm
Length of chord AB = 24 cm
To find,
Distance of the chord from the centre
📐 Figure
Chord AB of length 24 cm in a circle of diameter 26 cm A circle with centre O and radius 13 cm. Chord AB has length 24 cm. OM is perpendicular to AB and M is the midpoint of AB. Therefore AM and MB are each 12 cm. The right triangle OMA has hypotenuse OA equal to 13 cm and side AM equal to 12 cm. The distance OM is 5 cm. A B O M 13 cm ? 12 cm 12 cm AB = 24 cm
OA = 13 cm,   AM = MB = 12 cm,   OM = ?
✍️ Solution
Let AB be the chord and O be the centre of the circle. Draw OM ⟂ AB, where M lies on the chord AB.
Since the perpendicular from the centre of a circle to a chord bisects the chord,
AM = MB
Given that the length of chord AB is 24 cm,
AM = MB = 24 ÷ 2 = 12 cm
The diameter of the circle is 26 cm, so its radius is
OA = 26 ÷ 2 = 13 cm
In right-angled △OMA, by the Baudhāyana–Pythagoras theorem,
OA² = OM² + AM²
13² = OM² + 12²
169 = OM² + 144
OM² = 25
OM = 5 cm
✅ Final Answer
Distance from the centre to the chord = 5 cm

Class 9 Maths Chapter 5 End Exercise Question 4 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 4: Length of a Chord
A circle has a radius of 15 cm. A chord is drawn. The distance from the centre of the circle to the chord is 9 cm. What is the length of the chord?
✍️ Solution
Given,
Radius of the circle = 15 cm
Perpendicular distance of the chord from the centre = 9 cm
To find,
Length of the chord
📐 Figure
Chord AB at a distance of 9 cm from the centre O A circle with centre O and radius 15 cm. Chord AB lies below the centre. OM is perpendicular to AB and measures 9 cm. M is the midpoint of AB. The right triangle OMA has hypotenuse OA equal to 15 cm and OM equal to 9 cm. Therefore AM equals 12 cm and the complete chord AB equals 24 cm. A B O M 15 cm 9 cm 12 cm 12 cm AB = ?
OM ⟂ AB,   OM = 9 cm,   OA = 15 cm
✍️ Solution
Let AB be the chord of the circle and O be its centre. Draw OM ⟂ AB, where M lies on the chord AB.
Since the perpendicular from the centre of a circle to a chord bisects the chord,
AM = MB
Therefore, M is the midpoint of AB. Since AB = 24 cm is not yet known, let AM = MB = x cm.
In right-angled △OMA,
OA = 15 cm,    OM = 9 cm
By the Baudhāyana–Pythagoras theorem,
OA² = OM² + AM²
15² = 9² + AM²
225 = 81 + AM²
AM² = 144
AM = 12 cm
Since M is the midpoint of AB,
AB = AM + MB
AB = 12 + 12 = 24 cm
✅ Final Answer
Length of the chord = 24 cm

Class 9 Maths Chapter 5 End Exercise Question 5 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 5: Perpendicular Bisector of a Chord
Prove that the perpendicular bisector of a chord passes through the centre of the circle.
✍️ Solution
Given,
AB is a chord of a circle with centre O.
DE is the perpendicular bisector of AB, meeting AB at D.
Therefore, AD = DB and DE ⟂ AB.
To prove,
The perpendicular bisector DE passes through the centre O of the circle.
📐 Figure
Perpendicular bisector of chord AB and contradiction construction A circle has centre O and chord AB. D is the midpoint of AB. DE is the given perpendicular bisector of AB. For contradiction, O is initially shown not lying on DE, and OD is joined. The proof shows that OD must also be perpendicular to AB, forcing OD and DE to be the same line. A B D O E DE OD AB
Assume DE does not pass through O; join OD.
✍️ Proof
Let AB be a chord of the circle with centre O. Let DE be the perpendicular bisector of AB, meeting AB at D.
Since DE is the perpendicular bisector of AB,
AD = DB
DE ⟂ AB
Assume, for contradiction:
Suppose that the perpendicular bisector DE does not pass through the centre O.
Join OD.
Since D is the midpoint of chord AB, the line joining the centre O to the midpoint D of the chord is perpendicular to the chord.
OD ⟂ AB
Therefore,
∠ADO = 90°
∠ADE = 90°
Thus, through the same point D, both OD and DE are perpendicular to the same line AB.
But through a given point, only one perpendicular can be drawn to a given line.
Contradiction
Hence, OD and DE must be the same line. Therefore O must lie on DE.
This contradicts our assumption that DE does not pass through O.
Therefore, our assumption is false.
Hence, the perpendicular bisector DE of chord AB passes through the centre O of the circle.
✅ Hence Proved
The perpendicular bisector of a chord passes through the centre of the circle.

Class 9 Maths Chapter 5 End Exercise Question 6 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 6: Angle Subtended by a Diameter
The diameter of a circle is AB. Point C is on the circumference. What is the measure of ∠ACB? Explain your reasoning.
✍️ Solution
Given,
AB is the diameter of the circle.
O is the centre of the circle.
C is a point on the circumference.
To find,
Measure of ∠ACB
📐 Figure
Angle ACB subtended by diameter AB A circle with diameter AB and point C on the circumference. Joining CA and CB forms angle ACB at point C. Since AB is the diameter, the angle subtended by the diameter at the circumference is a right angle. A B C O AB — diameter ∠ACB = 90°
AB is a diameter, O is the centre and C lies on the circumference.
✍️ Solution
Since AB is the diameter of the circle and O is its centre, A, O and B lie on the same straight line.
Therefore, the angle subtended by the diameter AB at the centre O is a straight angle.
∠AOB = 180°
The angles ∠AOB and ∠ACB are subtended by the same chord AB at the centre and at the circumference, respectively.
By the Theorem 9 , the angle subtended by a chord at the circumference is half the angle subtended by the same chord at the centre.
∠ACB = 1 2 × ∠AOB
∠ACB = 1 2 × 180°
∠ACB = 90°
Thus, the angle made by the diameter AB at the point C on the circumference is a right angle.
✅ Final Answer
∠ACB = 90°

Class 9 Maths Chapter 5 End Exercise Question 7 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 7: Cyclic Quadrilateral Opposite Angles
ABCD is a cyclic quadrilateral inscribed in a circle. If ∠A measures 75°, what is the measure of ∠C? If ∠B measures 110°, what is the measure of ∠D?
✍️ Solution
Given,
ABCD is a cyclic quadrilateral.
∠A = 75°
∠B = 110°
To find,
∠C and ∠D
📐 Figure
Cyclic quadrilateral ABCD A cyclic quadrilateral ABCD is inscribed in a circle. Angles A and B are given as 75 degrees and 110 degrees. The opposite angles C and D are to be found. A B C D ∠A = 75° ∠B = 110° ∠C = ? ∠D = ?
ABCD is a cyclic quadrilateral; opposite angles are supplementary.
✍️ Solution
Since ABCD is a cyclic quadrilateral, its opposite angles are supplementary.
Therefore, ∠A and ∠C are opposite angles.
∠A + ∠C = 180°
75° + ∠C = 180°
∠C = 180° − 75°
∠C = 105°
Similarly, ∠B and ∠D are opposite angles.
∠B + ∠D = 180°
110° + ∠D = 180°
∠D = 180° − 110°
∠D = 70°
Thus, in a cyclic quadrilateral, each pair of opposite angles adds up to 180°.
✅ Final Answer
∠C = 105°     and     ∠D = 70°

Class 9 Maths Chapter 5 End Exercise Question 8 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 8: Cyclic Quadrilateral Opposite Angles
Quadrilateral PQRS is inscribed in a circle. If ∠P = (2x + 10)° and ∠R = (3x − 20)°, find the value of x and the measures of ∠P and ∠R.
✍️ Solution
Given,
PQRS is a cyclic quadrilateral.
∠P = (2x + 10)°
∠R = (3x − 20)°
To find,
The value of x and the measures of ∠P and ∠R
📐 Figure
Cyclic quadrilateral PQRS Quadrilateral PQRS is inscribed in a circle. P and R are opposite vertices, so their opposite angles are supplementary. P is represented by 2x plus 10 degrees and R by 3x minus 20 degrees. P Q R S ∠P = (2x + 10)° ∠R = (3x − 20)° P and R are opposite angles
P and R are opposite angles of the cyclic quadrilateral.
✍️ Solution
Since PQRS is a cyclic quadrilateral, its opposite angles are supplementary.
∠P and ∠R are opposite angles. Therefore,
∠P + ∠R = 180°
Substituting the given values,
(2x + 10)° + (3x − 20)° = 180°
2x + 10 + 3x − 20 = 180
5x − 10 = 180
5x = 180 + 10
5x = 190
x = 38
Now, substituting x = 38 in ∠P = (2x + 10)°,
∠P = (2 × 38 + 10)°
∠P = 76° + 10°
∠P = 86°
Similarly, substituting x = 38 in ∠R = (3x − 20)°,
∠R = (3 × 38 − 20)°
∠R = 114° − 20°
∠R = 94°
Check:
∠P + ∠R = 86° + 94° = 180°
Hence, the result satisfies the property of opposite angles of a cyclic quadrilateral.
✅ Final Answer
x = 38     ;     ∠P = 86°     ;     ∠R = 94°

Class 9 Maths Chapter 5 End Exercise Question 9 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 9: Radius of a Circle from a Chord
The distance of a chord of length 16 cm from the centre of a circle is 6 cm. Find the radius of the circle.
✍️ Solution
Given,
Length of chord AB = 16 cm
Distance of chord AB from the centre = 6 cm
To find,
Radius of the circle
📐 Figure
Chord AB of length 16 cm at a distance of 6 cm from centre O A circle with centre O contains chord AB of length 16 cm. OM is perpendicular to AB and measures 6 cm. Since the perpendicular from the centre to a chord bisects the chord, AM and MB are each 8 cm. Right triangle OMA has legs 6 cm and 8 cm, giving radius OA equal to 10 cm. A B O M r 6 cm 8 cm 8 cm AB = 16 cm
OM ⟂ AB,   OM = 6 cm,   AB = 16 cm
✍️ Solution
Let O be the centre of the circle and AB be the chord. Draw OM ⟂ AB, where M lies on AB.
Since the perpendicular from the centre of a circle to a chord bisects the chord,
AM = MB
Therefore, M is the midpoint of AB.
AM = MB = 16 2 = 8 cm
In right-angled △OMA,
OM = 6 cm,    AM = 8 cm
Also, OA is the radius of the circle. By the Baudhāyana–Pythagoras theorem,
OA² = OM² + AM²
OA² = 6² + 8²
OA² = 36 + 64
OA² = 100
Since OA is a length,
OA = 10 cm
Therefore, the radius of the circle is 10 cm.
✅ Final Answer
Radius of the circle = 10 cm

Class 9 Maths Chapter 5 End Exercise Question 10 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 10: Area of a Cyclic Quadrilateral
A cyclic quadrilateral has sides 5, 5, 12, 12 units. Find its area.
✍️ Solution
Given,
ABCD is a cyclic quadrilateral.
AB = BC = 5 units
CD = DA = 12 units
To find,
Area of quadrilateral ABCD
📐 Figure
Cyclic quadrilateral ABCD with sides 5, 5, 12 and 12 units, diagonal BD and right angles at A and C
BD divides the cyclic quadrilateral into two congruent right triangles.
✍️ Solution
Join diagonal BD.
In △ABD and △CBD,
AB = BC = 5 units
AD = CD = 12 units
BD = BD
Therefore,
△ABD ≅ △CBD
by SSS congruence.
By CPCT,
∠BAD = ∠BCD
Since ABCD is a cyclic quadrilateral, its opposite angles are supplementary.
∠BAD + ∠BCD = 180°
But ∠BAD = ∠BCD. Therefore,
2∠BAD = 180°
∠BAD = 90°
∠BCD = 90°
Hence, △ABD and △CBD are right-angled triangles, right-angled at A and C respectively.
Area of △ABD
= ½ × AB × AD
= ½ × 5 × 12
= 30 square units
Similarly,
Area of △CBD = 30 square units
Therefore,
Area of ABCD = Area of △ABD + Area of △CBD
= 30 + 30
= 60 square units
✅ Final Answer
Area of the cyclic quadrilateral = 60 square units

Class 9 Maths Chapter 5 End Exercise Question 11 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 11: Position of the Circumcentre of a Cyclic Quadrilateral
Consider a cyclic quadrilateral. Without drawing its circumcircle, how can we find out whether the centre of the circumcircle lies inside the quadrilateral or outside? What is the best way of finding out?
✍️ Solution
Given,
ABCD is a cyclic quadrilateral.
To find,
Whether the centre O of the circumcircle lies inside, on, or outside the quadrilateral.
Case 1: ∠ACB = ∠ADB < 90°
Case 1: ∠ACB = ∠ADB less than 90 degrees Cyclic quadrilateral ABCD. The angles ACB and ADB subtended by chord AB are less than 90 degrees. The circumcentre O lies inside ABCD. A B D C O ∠ADB < 90° ∠ACB < 90° AB — chord O lies INSIDE ABCD
Case 2: ∠ACB = ∠ADB = 90°
Case 2: ∠ACB = ∠ADB = 90°, AB is a diameter ABCD is a cyclic quadrilateral. A and B are endpoints of the diameter AB. The centre O lies exactly on AB. C and D lie exactly on the circle. Angles ACB and ADB are right angles. A B D C O ∠ADB = 90° ∠ACB = 90° AB is a diameter O lies ON AB
Case 3: ∠ACB = ∠ADB > 90°
Case 3: ∠ACB = ∠ADB greater than 90 degrees Cyclic quadrilateral ABCD with chord AB. The angles ACB and ADB subtended by chord AB are greater than 90 degrees. The circumcentre O lies outside ABCD, on the opposite side of AB from C and D. A B D C O ∠ADB > 90° ∠ACB > 90° AB — chord O lies OUTSIDE ABCD
✍️ Explanation
Let ABCD be a cyclic quadrilateral and take AB as a chord.
The chord AB subtends ∠ACB at C and ∠ADB at D. Since both angles stand on the same chord AB,
∠ACB = ∠ADB
We now compare this common angle with 90°.
Case 1: ∠ACB = ∠ADB < 90°
The angle subtended by chord AB at the circumference is less than 90°.
Therefore, the corresponding central angle is less than 180°. Hence the centre O lies on the same side of AB as C and D.
O lies INSIDE ABCD
Case 2: ∠ACB = ∠ADB = 90°
A chord that subtends a right angle at the circumference is a diameter.
AB is a diameter
O lies ON AB
Case 3: ∠ACB = ∠ADB > 90°
The angle subtended by chord AB at the circumference is greater than 90°.
Therefore, the centre O lies on the opposite side of AB from C and D.
O lies OUTSIDE ABCD
Thus, by observing the angles subtended by the same chord AB, we can determine the position of the centre O without drawing the circumcircle.
✅ Final Answer
∠ACB = ∠ADB < 90° → O lies inside ABCD
∠ACB = ∠ADB = 90° → O lies on AB
∠ACB = ∠ADB > 90° → O lies outside ABCD

Class 9 Maths Chapter 5 End Exercise Question 12 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 12: Equal Intersecting Chords
When two chords intersect, each of them is divided into two line segments. Show that if the intersecting chords are of equal length, then the line segments of one chord are equal to the corresponding line segments of the other chord.
✍️ Solution
Given,
Chords AB and CD of a circle intersect at P.
AB = CD
To prove that,
AP = CP and PB = PD
Construction,
Draw OM ⟂ AB and ON ⟂ CD, where O is the centre of the circle.
📐 Construction
Equal intersecting chords AB and CD with centre O and perpendiculars OM and ON
Proof
In △OMP and △ONP,
OM = ON
Equal chords of a circle are equidistant from the centre.
OP = OP
(Common)
∠OMP = ∠ONP = 90°
(By construction)
∴ △OMP ≅ △ONP
(By RHS congruence rule)
Therefore, by CPCT,
MP = PN  — (i)
Also,
AB = CD
Since the perpendicular from the centre of a circle bisects a chord,
MB = ½AB
DN = ½CD
∴ MB = DN  — (ii)
From (i) and (ii),
MB − MP = DN − PN
Therefore,
PB = PD  — (iii)
Again, since
AB = CD
and
MB = DN   and   MP = PN,
the corresponding remaining parts are equal:
AP = CP
Hence, the line segments of one chord are equal to the corresponding line segments of the other chord.
✅ Hence Proved
AP = CP    and    PB = PD

Class 9 Maths Chapter 5 End Exercise Question 13 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 13: Construction of a Circle with a Chord
Draw a circle in which a chord of 6 cm length stands at a distance of 3 cm from the centre.
Hint: Is it a circumcircle of a suitable triangle?
✍️ Solution
Given,
Chord AB = 6 cm.
Distance of the chord from the centre = 3 cm.
To construct,
A circle having a chord of length 6 cm at a perpendicular distance of 3 cm from its centre.
Construction
1. Draw a line segment AB = 6 cm.
2. Construct the perpendicular bisector of AB using equal arcs with A and B as centres. Let it meet AB at M.
3. On the perpendicular bisector, take a point O such that OM = 3 cm.
4. With O as centre and OA as radius, draw the circle.
Hint: The hint asks us to think whether the required circle can be regarded as the circumcircle of a suitable triangle. It is a guiding idea connecting the construction with the circumcircle concept; we do not need to calculate the radius separately.
📐 Construction Figure
Construction of a circle with a 6 cm chord at 3 cm from the centre
✓ Verification
Since M is the midpoint of AB,
AM = MB = 3 cm
Therefore,
AB = AM + MB = 3 + 3 = 6 cm
Also, by construction,
OM = 3 cm
and
OM ⟂ AB
Hence, the perpendicular distance of chord AB from the centre O is exactly 3 cm. Therefore, the constructed circle satisfies both the given conditions.
✅ Required Circle Constructed
Chord AB = 6 cm   and   distance of AB from centre O = 3 cm

Class 9 Maths Chapter 5 End Exercise Question 14 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 14: Cyclic Parallelogram and Rectangle
Show that rectangle is the only parallelogram that can be inscribed in a circle.
✍️ Solution
Given,
ABCD is a parallelogram inscribed in a circle.
To Prove,
ABCD is a rectangle.
📐 Cyclic Parallelogram ABCD
Cyclic parallelogram ABCD with opposite angles A and C ABCD is a parallelogram inscribed in a circle. All four vertices A, B, C and D lie exactly on the circumference. Opposite angles A and C are marked. A B C D O ∠A ∠C ∠A = ∠C
Proof
Since ABCD is a parallelogram,
∠A = ∠C
because opposite angles of a parallelogram are equal.
Also, ABCD is a cyclic quadrilateral. Therefore,
∠A + ∠C = 180°
because opposite angles of a cyclic quadrilateral are supplementary.
Since
∠A = ∠C
we get
∠A + ∠A = 180°
2∠A = 180°
∠A = 90°
Therefore,
∠C = 90°
Also, adjacent angles of a parallelogram are supplementary. Therefore,
∠A + ∠B = 180°
Since
∠A = 90°
we get
∠B = 90°
Similarly,
∠D = 90°
Hence all four angles of ABCD are right angles.
Therefore, ABCD is a rectangle.
✅ Hence Proved
A parallelogram that can be inscribed in a circle is necessarily a rectangle.

Class 9 Maths Chapter 5 End Exercise Question 15 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 15: Rectangle Inscribed in a Circle
Show that if a rectangle is inscribed in a circle, then the point of intersection of its diagonals is the centre of the circle.
✍️ Solution
Given,
ABCD is a rectangle inscribed in a circle. Its diagonals AC and BD intersect at O.
To Prove,
O is the centre of the circle.
📐 Rectangle ABCD Inscribed in a Circle
Rectangle ABCD inscribed in a circle with intersecting diagonals AC and BD Rectangle ABCD is inscribed in a circle. All four vertices A, B, C and D lie exactly on the circumference. Diagonals AC and BD intersect at O, the centre of the circle. Right angles at A and D show that AC and BD are diameters. A B C D O 90° 90° AC BD
Proof
Since ABCD is a rectangle,
∠ADC = 90°
The angle ∠ADC is an angle at the circumference standing on chord AC.
An angle in a semicircle is 90°. Therefore, the chord AC is a diameter of the circle.
Similarly, since ABCD is a rectangle,
∠DAB = 90°
The angle ∠DAB stands on chord DB.
Since an angle in a semicircle is 90°, DB is also a diameter of the circle.
Thus, AC and BD are two diameters of the same circle.
The two diameters intersect at O. The point of intersection of two diameters of a circle is its centre.
Therefore, O is the centre of the circle.
✅ Hence Proved
The point of intersection of the diagonals of a rectangle inscribed in a circle is the centre of the circle.

Class 9 Maths Chapter 5 End Exercise Question 16 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 16: Midpoints of Equal Chords
Consider all chords of a circle of a fixed length. What is the shape formed by the midpoints of all these chords?
✍️ Solution
Given,
A circle with centre O is given. Consider all chords of the circle having the same fixed length.
To Find,
The shape formed by the midpoints of all these equal chords.
📐 Midpoints of Equal Chords
Midpoints of equal chords forming a concentric circle A given circle with centre O contains several equal chords in different positions. The midpoints of these chords are all at the same distance from O and lie on a smaller concentric circle. O M₁ M₂ M₃ M₄ M₅ M₆ OM₁ = OM₂ = OM₃ = … Locus of midpoints
Proof
Let AB and CD be any two equal chords of the circle, and let their midpoints be M and N respectively.
By Theorem 6 , equal chords of a circle are equidistant from the centre. Therefore,
OM = ON
Since all the chords have the same fixed length, the midpoint of every such chord is at the same fixed distance from O.
OM = ON = OP = OQ = …
Thus, all the midpoints are equidistant from the fixed point O.
The locus of all points at a fixed distance from a fixed point is a circle. Hence, the midpoints of all these chords form a circle with centre O. It is therefore concentric with the given circle.
✅ Final Answer
The midpoints of all chords of a fixed length form a circle concentric with the given circle.

Class 9 Maths Chapter 5 End Exercise Question 17 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 17: Congruent Chords and Angle Bisector
In a circle with centre O, chords AB and AC are congruent. Explain why this statement is true: “The centre of the circle lies on the angle bisector of ∠BAC”.
✍️ Solution
Given,
In a circle with centre O, AB and AC are congruent chords.
To Prove,
O lies on the angle bisector of ∠BAC.
Construction
Draw OM ⟂ AB and ON ⟂ AC. Join OA.
📐 Congruent Chords AB and AC
Circle with centre O and congruent chords AB and AC A circle with centre O. Congruent chords AB and AC have midpoints M and N. OM is perpendicular to AB and ON is perpendicular to AC. OA is joined to show the angle bisector of angle BAC. A B C O M N ∠BAO ∠OAC AB = AC AO ∠BAO = ∠OAC
Proof
The two chords are congruent. Therefore,
AB = AC
½ AB = ½ AC
AM = AN [Perpendicular from the centre bisects the chord]
In triangles △AOM and △AON,
OA = OA [Common side]
OM = ON [Equal chords are equidistant from the centre]
AM = AN [Already proved]
Hence,
△AOM ≅ △AON [SSS]
Therefore, corresponding angles are equal:
∠MAO = ∠OAN
Since M lies on AB and N lies on AC,
∠BAO = ∠OAC
Thus, AO divides ∠BAC into two equal angles. Hence, the centre O lies on the angle bisector of ∠BAC.
✅ Hence Proved
The centre O of the circle lies on the angle bisector of ∠BAC.

Class 9 Maths Chapter 5 End Exercise Question 18 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 18:Ditance between chords
Two parallel chords of lengths 10 cm and 24 cm are on the same side of the centre of a circle. The distance between the chords is 7 cm. Find the radius of the circle.
✍️ Solution
Given,
AB = 10 cm, CD = 24 cm
Distance between chords = 7 cm
To Find,
Radius of the circle = R
📐 Parallel Chords
Class 9 Maths Question 18 — Two Parallel Chords on the Same Side A circle with centre O has two parallel chords AB and CD on the same side of the centre. OM is perpendicular to AB at midpoint M and ON is perpendicular to CD at midpoint N. The half chord lengths are 5 cm and 12 cm and the distance between the chords is 7 cm. A B C D O M N 5 cm 12 cm 7 cm R
Solution
AM = ½ AB = ½ × 10 = 5 cm [Perpendicular from centre bisects the chord]
CN = ½ CD = ½ × 24 = 12 cm [Perpendicular from centre bisects the chord]
Since the two chords are on the same side of the centre,
OM − ON = 7
ON = OM − 7
In right triangle △OMA,
OA² = OM² + AM²
R² = OM² + 5²
In right triangle △ONC,
OC² = ON² + CN²
R² = ON² + 12²
Since OA = OC = R,
OM² + 5² = ON² + 12²
Substituting ON = OM − 7,
OM² + 25 = (OM − 7)² + 144
OM² + 25 = OM² − 14OM + 49 + 144
14OM = 168
OM = 12 cm
Using right triangle △OMA,
R² = 12² + 5²
R² = 144 + 25 = 169
R = 13 cm
✅ Final Answer
Radius of the circle = 13 cm

Class 9 Maths Chapter 5 End Exercise Question 19 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Chapter 5 End Exercise: Question 19
A regular hexagon is inscribed in a circle of radius r. Find the length of the sides of the hexagon and the distance of each side from the centre of the circle.
✍️ Solution
Given,
Regular hexagon ABCDEF is inscribed in a circle of radius r.
To Find,
1. Length of each side.
2. Distance of each side from the centre.
📐 Regular Hexagon Inscribed in a Circle
Class 9 Maths Question 19 — Regular Hexagon Inscribed in a Circle A regular hexagon ABCDEF is inscribed in a circle with centre O and radius r. OA and OB are radii forming a 60 degree central angle. OM is perpendicular to side AB at its midpoint M. A B C D E F O M r 60°
Solution
A regular hexagon divides the circle into 6 equal central angles.
∠AOB = 360° 6 = 60°
In triangle △AOB,
OA = OB = r [Radii of the same circle]
∠AOB = 60°
Therefore, the other two angles of △AOB are also 60°. Hence, △AOB is an equilateral triangle.
AB = OA = r
Therefore, the length of each side of the regular hexagon is
r
Now draw OM ⟂ AB, where M is the midpoint of AB.
AM = 1 2 AB = r 2 [Perpendicular from centre bisects the chord]
In right triangle △OMA,
OA² = OM² + AM²
r² = OM² + ( r 2 )²
OM² = r² − r² 4
OM² = 3r² 4
OM = √3r 2
By symmetry, all six sides of the regular hexagon are equidistant from the centre. Therefore, the distance of each side from the centre is
√3r 2
✅ Final Answer
Length of each side = r    |    Distance of each side from centre = √3r 2

Class 9 Maths Chapter 5 End Exercise Question 20 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 20: A quadrilateral MNOP
A quadrilateral MNOP is inscribed in a circle. If MN is a diameter, what can you say about ∠MOP and ∠MNP? Explain your reasoning.
✍️ Solution
Given,
Quadrilateral MNOP is inscribed in a circle and MN is a diameter.
To Find,
Relation between ∠MOP and ∠MNP.
📐 Cyclic Quadrilateral MNOP
Class 9 Maths Chapter 5 Question 20 cyclic quadrilateral MNOP with MN as diameter showing angles MOP and MNP on the same chord MP
Solution
The angles ∠MOP and ∠MNP stand on the same chord MP.
Also, the points O and N lie on the same segment of the circle with respect to chord MP.
Therefore, by the theorem “Angles in the same segment of a circle are equal”,
∠MOP = ∠MNP
[Angles in the same segment of a circle]
Since MN is a diameter, the angle subtended by it at P is a right angle.
∠MPN = 90°
[Angle in a semicircle is a right angle]
This additional fact is not required for the required relationship between ∠MOP and ∠MNP.
✅ Final Answer
∠MOP = ∠MNP
They are equal because they stand on the same chord MP and lie in the same segment of the circle.

Class 9 Maths Chapter 5 End Exercise Question 21 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 21: Exterior Angle of a Cyclic Quadrilateral
Let ABCD be a cyclic quadrilateral. Explain why the exterior angle at any vertex is equal to the interior opposite angle.
Example: ∠ADE = ∠ABC, where E is a point on the extension of side AD.
✍️ Solution
Given,
ABCD is a cyclic quadrilateral and AD is extended to E.
To Prove,
∠ADE = ∠ABC
Cyclic quadrilateral ABCD with AD extended to E showing exterior angle ADE and opposite interior angle ABC
Solution
Since AD is extended to E,
∠ADE + ∠ADC = 180°
[Linear pair]
Also, ABCD is a cyclic quadrilateral. Therefore,
∠ADC + ∠ABC = 180°
[Opposite angles of a cyclic quadrilateral]
Comparing the two equations,
∠ADE + ∠ADC = ∠ADC + ∠ABC
∠ADE = ∠ABC
[Subtracting ∠ADC from both sides]
✅ Hence Proved
∠ADE = ∠ABC
Thus, the exterior angle at a vertex of a cyclic quadrilateral is equal to its interior opposite angle.

Class 9 Maths Chapter 5 End Exercise Question 22 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 22: Longest Chord of a Circle
“There is no chord of a circle that is longer than its diameter.” How do you justify this statement?
✍️ Solution
Given,
Let AB be any chord of a circle with centre O and radius r.
To Prove,
No chord of the circle is longer than its diameter.
Circle with centre O and chord AB showing that the chord cannot be longer than the diameter
Solution
Join OA and OB.
In triangle △AOB,
OA + OB > AB
[Triangle inequality]
Since OA = OB = r,
2r > AB
But,
Diameter = 2r
Therefore,
AB < Diameter
If the chord passes through the centre O, then it becomes the diameter itself.
AB = Diameter
[A diameter is also a chord]
✅ Hence Proved
The diameter is the longest chord of a circle.
Therefore, no chord can be longer than the diameter.

Class 9 Maths Chapter 5 End Exercise Question 23 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 23: Shortest Chord Through an Interior Point
Let A be any point within a given circle with centre O. Show that the shortest chord of the circle that passes through point A is the one that is perpendicular to OA.
✍️ Solution
Given,
A is any point inside a circle with centre O.
To Prove,
The shortest chord passing through A is perpendicular to OA.
Circle with centre O and an interior point A showing that the shortest chord through A is perpendicular to OA
Solution
Let BC be any chord passing through A, and let M be the midpoint of BC.
Since M is the midpoint of chord BC,
OM ⟂ BC
[Perpendicular from the centre bisects a chord]
In right triangle △OMA,
OA² = OM² + AM²
Therefore,
OM² = OA² − AM²
If the radius of the circle is r, then
BC = 2√(r² − OM²)
Substituting OM² = OA² − AM²,
BC = 2√(r² − OA² + AM²)
Here, r² − OA² is fixed. Therefore, BC is shortest when
AM = 0
Hence,
M = A
Since OM ⟂ BC,
OA ⟂ BC
[As M = A]
✅ Hence Proved
The shortest chord passing through A is the chord perpendicular to OA.

Class 9 Maths Chapter 5 End Exercise Question 24 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 24: Angle in a Semicircle
How would you use the following figure to justify the statement that the angle in a semicircle is 90°?
✍️ Solution
Given,
BC is a diameter of the circle with centre O, and A is a point on the circle.
To Prove,
∠BAC = 90°
Class 9 Maths Chapter 5 Question 24 – Angle in a Semicircle is 90 Degrees A circle with centre O and diameter BC. Point A lies exactly on the circle. OA is joined to the centre, forming two isosceles triangles AOB and AOC. The base angles are marked a and b. The figure illustrates the proof that angle BAC in a semicircle is 90 degrees. A B C O a b
Solution
Since OA = OB (radii of the circle),
∠OAB = ∠ABO = a
[Angles opposite equal sides of an isosceles triangle]
Also, OA = OC (radii of the circle),
∠OAC = ∠ACO = b
[Angles opposite equal sides of an isosceles triangle]
Therefore,
∠BAC = ∠BAO + ∠OAC
∠BAC = a + b
In triangle △ABC,
a + (a + b) + b = 180°
[Angle sum property of a triangle]
2(a + b) = 180°
a + b = 90°
But,
∠BAC = a + b
∠BAC = 90°
✅ Hence Proved
The angle in a semicircle is 90°.

Class 9 Maths Chapter 5 End Exercise Question 25 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Crcle
Question 25: Perpendicular Chords and Their Midpoints
In a circle, two chords CC′ and DD′ are drawn perpendicular to a diameter AB. Prove that the segment MM′ joining the midpoints of the chords CD and C′D′ is perpendicular to AB.
✍️ Solution
Given,
AB is a diameter of the circle. CC′ and DD′ are chords perpendicular to AB.
M and M′ are the midpoints of CD and C′D′, respectively.
To Prove,
MM′ ⟂ AB
Class 9 Maths Chapter 5 Question 25 showing two unequal chords CC prime and DD prime perpendicular to diameter AB, with M and M prime as midpoints of CD and C prime D prime
Proof
We have,
CC′ ⟂ AB
[Given]
DD′ ⟂ AB
[Given]
Since CC′ and DD′ are both perpendicular to AB,
CC′ ∥ DD′
[Perpendicular to the same line]
Therefore, CC′D′D is a trapezium, with CC′ and DD′ as its parallel sides.
M is the midpoint of CD, and M′ is the midpoint of C′D′.
Thus, CD and C′D′ are the two non-parallel sides of the trapezium.
The segment joining the midpoints of the two non-parallel sides of a trapezium is parallel to its parallel sides.
MM′ ∥ CC′
[Midpoint theorem for a trapezium]
But,
CC′ ⟂ AB
[Given]
Since MM′ ∥ CC′,
MM′ ⟂ AB
[Since MM′ ∥ CC′ and CC′ ⟂ AB]
✅ Hence Proved
MM′ ⟂ AB

Class 9 Maths Chapter 5 End Exercise Question 26 Solution

Ganita Manjari | Chapter 5 End-of-Chapter Exercise | Circle
Question 26: Opposite Angles of a Cyclic Quadrilateral
How would you use the following figure to justify the statement that the sum of the opposite angles of a cyclic quadrilateral is 180°?
✍️ Solution
Given,
ABCD is a cyclic quadrilateral. AC and BD pass through the centre O of the circle.
To Prove,
∠DAB + ∠BCD = 180°
Class 9 Maths Chapter 5 Question 26 cyclic quadrilateral ABCD with centre O and angles p q u v
Proof
Since OA = OB = OC = OD, the four triangles AOB, BOC, COD and DOA are isosceles triangles.
Therefore, their equal base angles are respectively p, p; q, q; u, u; and v, v.
The four angles of quadrilateral ABCD are:
∠DAB = p + v
[From the figure]
∠ABC = p + q
[From the figure]
∠BCD = q + u
[From the figure]
∠CDA = u + v
[From the figure]
The sum of the four angles of a quadrilateral is 360°.
(p + v) + (p + q) + (q + u) + (u + v) = 360°
2(p + q + u + v) = 360°
p + q + u + v = 180°
Rearranging the above result,
(p + v) + (q + u) = 180°
But,
∠DAB = p + v
[From the figure]
∠BCD = q + u
[From the figure]
Therefore,
∠DAB + ∠BCD = 180°
✅ Hence Proved
The sum of a pair of opposite angles of a cyclic quadrilateral is 180°.

📚 Continue Learning

Congratulations! You have completed the Class 9 Maths Chapter 5 End-of-Chapter Exercises. You have now revised the complete Chapter 5 through its 26 end-of-chapter questions. Continue your preparation by revisiting any exercise for practice or moving to another chapter.


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❓ Frequently Asked Questions

Find quick answers to common questions about Class 9 Maths Chapter 5 End of Chapter Exercises Solutions. These FAQs help students understand the exercise, its coverage, and how to use the complete solutions effectively for homework, revision, self-study, and CBSE examination preparation.

What are the End-of-Chapter Exercises in Class 9 Maths Chapter 5?

The End-of-Chapter Exercises are the final set of practice questions given at the end of Chapter 5 – I’m Up and Down, and Round and Round in the NCERT Ganita Manjari (2026) textbook. They bring together the major concepts and applications covered throughout the chapter.

How many questions are there in Chapter 5 End-of-Chapter Exercises?

There are 26 questions in the End-of-Chapter Exercises. The questions are presented in the same order as the textbook and include different types of practice, proof, application, construction, and higher-order questions.

What topics are covered in the Chapter 5 End Exercises?

The End-of-Chapter Exercises revise a wide range of Chapter 5 topics, including chords, distance from the centre, angles subtended by arcs, diameter-related results, concyclicity, cyclic quadrilaterals, intersecting chords, constructions, and applications involving circles. The complete set also includes proof-based and higher-order questions.

Are the Chapter 5 End Exercises useful for revision?

Yes. The End-of-Chapter Exercises are especially useful for complete Chapter 5 revision because they bring together different types of questions from the chapter. Students can use the question-wise solutions to identify weak areas and practise before tests and examinations.

Are there higher-order questions in the Chapter 5 End Exercises?

Yes. The exercise includes several questions marked with an asterisk (*) in the textbook. These questions require deeper reasoning, proof, construction, or application of the concepts developed in Chapter 5.

Are these solutions suitable for CBSE Class 9 students?

Yes. The solutions are presented in a clear, student-friendly, step-by-step CBSE answer-writing style. They can be used for classroom practice, homework, self-study, revision, and examination preparation.

Can I jump directly to a particular question?

Yes. A dedicated Jump to Any Question navigator is provided on this page. Students can select any question from Q1 to Q26 and move directly to its solution without scrolling through the complete exercise.

Are these Class 9 Maths Chapter 5 End-of-Chapter Solutions based on Ganita Manjari 2026?

Yes. These Class 9 Maths Chapter 5 End of Chapter Exercises Solutions are prepared according to the latest NCERT Ganita Manjari (2026) textbook. The questions are followed in textbook order and the solutions are presented in a student-friendly format for learning, revision, and CBSE preparation.

📚 Useful Learning Resources

Continue your Class 9 Maths preparation with trusted resources from Maths Gurukulam and official NCERT and CBSE sources. These links can help you access textbooks, syllabus information, and academic updates.

Rakesh Kumar Singh - Mathematics Educator
👨‍🏫 Reviewed & Prepared By

Rakesh Kumar Singh

Founder, Maths Gurukulam & Newton Study Point
Teaching Mathematics Since 2006

These Class 9 Maths Chapter 5 End-of-Chapter Exercises Solutions are carefully prepared according to the latest NCERT Ganita Manjari (2026) and the CBSE curriculum. The complete set of 26 questions is presented in a clear, step-by-step format to help students practise, revise, and prepare confidently for Class 9 Mathematics examinations.

📘 NCERT Ganita Manjari (2026) 🎯 CBSE Aligned 📝 Step-by-Step Solutions 💡 Concept-Based Learning
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