Question

In decreasing the radius of a circle by 30%,its area is decreased by

Answer 1

please see the attachment

Answer 2

Let radius of circle be r.

Area of circle = pi.r^2

Radius decreases = 30%

New radius is r - 50%of r = 0.7 r

New area = 3.14 * (.7r)^2

               = 0.49 * 3.14 * r^2

Hence decreasing in area = 51%