


Given length of tangent AB = 24 cm
Distance from centre of the circle to point B = 25 cm
Let OA is the radius of the circle.
Now from Pythagoras Theorem,
OB2 = OA2 + AB2
=> 252 = OA2 + 242
=> 625 = OA2 + 576
=> OA2 = 625 - 576
=> OA2 = 49
=> OA = √49
=> OA = 7
So radious of the circle = 7 cm
