Question

The radii of 2 concentric circles is 13cm and 8cm. AB is a diameter of bigger circle and BD is tangent to smaller circle touching it at D and intersecting the larger circle at P, on producing. Find length AP

Answer 1

r= 8cm

R=13cm

angle ODB= 90 degrees ( BD is tangent)

angle APB =90 degrees ( angle in semicircle)

angle DB0 =ANGLE PBA (COMMON)

SO, BY AA criteria tri APB similar to tri DBO

BY CPST ...... BD/BP=BO/AB= OD/ AP

OD/AP= BO/AB

8/AP=13/26

AP=16 cm