Question

The length of the tangent to a circle from a point P, which is 25 cm away from the centre is 24 cm. What is the radius of the circle?

Answer 1

Let the radius AB be r.

In the right ∆ABO,

OB² = OA² + AB²

25² = 24² + r² 

25² – 24² = r²

(25 + 24) (25 – 24) = r² 

r = `sqrt(49)` = 7

Radius of the circle = 7 cm