When the radius of a circle is increased by 1 cm, its area increases by 22 cm². What was the original radius of the circle?

Explanation

Let the radius of the circle be r cm new radius of the circle = (r + 1) As we know, Area of the circle = πr² According to the question π (r + 1) ² – πr² = 22 2 2 π [ r+ 1) -r ] = 22 (22/7) [r² + 1 + 2r - r² ] = 22 (1 + 2r) = 7 2r = 7-1 r = 6/2 r = 3 cm.