Question

In the adjoining figure, PA and PB are tangents to a circle with centre O. The measure of angle APB is

In the adjoining figure, XY and X'Y' are parallel tangents to a circle with centre O. Another tangent AB touches the circle at C intersecting XY at A and X'Y' at B. Prove that AB subtends right angle at the centre of the circle; or ∠AOB = 90°.

A parallelogram having one of its sides 5 cm circumscribes a circle. The perimeter of parallelogram is :

Assertion (A) : Tangents drawn at the end points of a diameter of a circle are always parallel to each other. Reason (R) : The lengths of tangents drawn to a circle from a point outside the circle are always equal.