If the radius of a circle is increased by 1%, l then the area of that circle increases by what percent?

If the radius of a circle is increased by 1%, l then the area of that circle increases by what percent?

A 1.01%

B l.l%

C 2.l%

D 2.01%

Solution

Correct Answer: Option D

Area of first circle= Pi*r2

Area of second circle= Pi*(1.01r)2 = Pi*1.0201r2

Percentage increase = (Pi*1.0201r2 - Pi*r2 ) * 100 / Pi*r2

= (1.0201 - 1) * 100

= 2.01%