Question

In the given figure, O is the centre of two concentric circles of radii 5 cm and 3 cm. From an external point p tangents PA and PB are drawn to these circles. If PA = 12 cm then PB is equal to

Answer 1

Then, OB = 3 cm 

Now, ∠OAP = 90^o (Tangents drawn from an external point are perpendicular to the radius at the point of contract)