In Fig. 10.36, A,B and C are three points on a circle with centre O such that ∠ BOC = 30° and∠ AOB = 60°. If D is a point on the circle other than the arc ABC, find ∠ADC.

Question

Philoid · Accepted Answer

∠AOC = ∠AOB + ∠BOC

= 60° + 30°

= 90°

We know that angle subtended by an arc at the centre is double the angle subtended by it any point on the remaining part of the circle

∠ADC = ∠AOC

= * 90^o

= 45^o