## Chapter 10 Circles Exercise 10.2

**Question 1: Recall that two circles are congruent if they have the same radii. Prove that equal chords of congruent circles subtend equal angles at their centres.**

Answer:In ∆ AOB and ∆ DOC

Answer:

OA = OC (Radii of the circle)

OB = OD (Radii of the circle)

AB = CD (Given)

Therefore, ∆ AOB ≅ ∆ COD (SSS rule). By CPCT, ∠AOB = ∠COD

**Question 2: Prove that if chords of congruent circles subtend equal angles at their centres, then the chords are equal.**

Answer:

Answer:

OA = OC (Radii of the circle)

∠AOB = ∠COD (Given)

OB = OD (Radii of the circle)

Therefore, ∆ AOB ≅ ∆ COD (SAS rule). By CPCT, AB = DC.

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