Question 6 - End-of-Chapter Exercises - Chapter 5 Class 9 - I’m Up and Down, and Round and Round (Ganita Manja
Last updated at May 26, 2026 by Teachoo
End-of-Chapter Exercises
Question 1
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Class 9
Chapter 5 Class 9 - I’m Up and Down, and Round and Round (Ganita Manja
- Definitions
- Symmetries of Circle
- Number of Circles
- Exercise Set 5.1
- Think, Draw and Infer (Page 98)
- Angle Subtended by Chords
- Exercise Set 5.2
- Mid-points and Perpendicular Bisectors of Chords
- Exercise Set 5.3
- Distance of Chords from the Centre
- Exercise Set 5.4
- Distance of unequal chords from center
- Exercise Set 5.5
- Angle subtended by an arc
- Exercise Set 5.6
- Concyclicity of Points and Cyclic Quadrilateral
- Theorems (and their Proofs)
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End-of-Chapter Exercises
Transcript
Question 6 The diameter of a circle is AB . Point C is on the circumference. What is the measure of the ∠ACB? Explain your reasoning. We know that Angle in a semicircle is always a right angle Thus, ∠ ACB = 90° Let’s look at the same statement, in detail Now, AOB is a straight line passing through center O. ∴ Angle subtended by arc AB at O is ∠AOB = 180° By Theorem 9: The angle subtended by an arc at the centre is double the angle subtended by it at any point on the remaining part of the circle. Thus, ∠ AOB = 2∠ACB (∠ 𝐴𝑂𝐵)/2 = ∠ ACB (180° )/2 = ∠ ACB 90° = ∠ ACB ∠ ACB = 90°
