# If the area of a circle is 25pi cm^2, what is the circle's circumference?

Jun 19, 2015

Circumference = $10 \pi$ cm.

#### Explanation:

Area of circle = $\pi {r}^{2} = 25 \pi c {m}^{2}$
$\Rightarrow {r}^{2} = 25 c {m}^{2}$
$\Rightarrow r = 5 c m$

Circumference of circle = $\pi 2 r = \pi \cdot 2 \cdot 5 c m = 10 \pi c m$