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 : obtuse ∠AOB,
Give reasons for your answers clearly.
Obtuse ∠AOB = 2°∠APB = 2a°
(Angle at the centre is double the angle at the circumference subtended by the same chord)