Question

Find the radius and the circumference of a circle whose area is $144\pi {\text{cm}}^2$.

Answer 1

REF.Image

area = $\pi r^2$

$\pi r^2=144\pi c{m}^2$

$\therefore r=\sqrt{144}$

$r=12$

circumference = $2\pi r$

$=2\times \pi \times 12$

$=24\pi$

radius = 12

circumference = $24\pi$