Question

In figure, there are two concentric circles,
with centre O and of radii 5 cm and 3 cm.
From an external point P, tangents PA and
PB are drawn to these circles. If AP = 12
cm, find the length of BP.​

Answer 1

Answer:

Two concentric circles with center O.

OA is 5 cm and OB is 3 cm.

Join OP.

Now, in △OAP

∠OAP=90°(Angles between radius and tangent)

OA² + AP² = OP²

5² + 12² = OP²

OP = 13 cm

In △OBP,

OB² + BP² = OP²

3² + BP² = 13²

BP = √160 = 4√10cm