Question

The figure shows two circles which intersect at A and B. The centre of the smaller circle is O and lies on the circumference of the larger circle. Given that ∠APB = a°.

Calculate, in terms of a°, the value of : ∠ADB.

Give reasons for your answers clearly.

Answer 1

Join AB.

∠ADB = ∠ACB = 180° – 2a° 

(Angle subtended by the same arc on the circle are equal)