Question

If the radius of a circle decreases by 10%. find the % change in the area of the circle./

Answer 1

Original Radius = 10

Original Area = pi(R^2) = 100pi

New Radius = 9

New Area = pi(R^2) = 81pi

Percentage Change = (New - Old)/Old = (81pi - 100pi)/100pi = -19pi/100pi = -19% = 19% decrease