Question

If the length of a tangent drawn from a external point 'p' of a circle is 7.5cm. The distance from 'p' to the centre of a circle is 12.5cm then find the radius of a circle

please solve this​

Answer 1

in circle,BP is a tangent

OP is a segment drawn from centre of circle to the point p

BP=7.5

OP=12.5,OB=?

In PBO, angle PBO=90

by Pythagoras theorem

${op }^{2} = {bp}^{2} + {ob}^{2}$

12.5*12.5=7.5*7.5+ob*ob

156.25-56.25=ob*ob

ob*ob=100

ob=10

therefore radius =10cm