Question

What is the circumference of a circle with area = `36 pi` `cm^2`?

Answer 1

The area of a circle with radius `r` is given by `A=pi*r^2` and the circumference
by `S=2*pi*r`

But `A=36*pi=>pi*r^2=36*pi=>r=6cm`

hence `S=2*pi*6=12*pi` cm