# The area of a circle is 64pi cm^2, how do you find its radius?

Oct 25, 2016

$r = 8 c m$

#### Explanation:

We know the formula for calculating the area of a circle is $A = \pi \cdot {r}^{2}$ where $r$ is the radius.

Substituting what we know:

$64 \pi c {m}^{2} = \pi {r}^{2}$ we solve for $r$

$64 \pi \frac{c {m}^{2}}{\pi} = \pi {r}^{2} / \pi$

$64 c {m}^{2} = {r}^{2}$

$\sqrt{64 c {m}^{2}} = \sqrt{{r}^{2}}$

$r = 8 c m$