Question

What is the radius of a circle with an area of 32.1 sq ft

Answer 1

Area of circle = 32.1

$\pi * r^{2} = 32.1$

$r^{2} = \frac{32.1}{ \pi }$

$r = \sqrt{ \frac{32.1}{ \pi } }$ = 3.2 ft

Answer 2

We can rearrange the formula for finding the area of circle to get the radius of a circle from the area. 

Formula: $A = \pi r^2$

Rearrange the formula.

$A = \pi r^2 \\ \\ \frac{A}{\pi} = r^2 \\ \\ \sqrt{\frac{A}{\pi}} = r$

We let $\pi$ equal to 3.14.

Plug in the values.

$\sqrt{\frac{32.1}{3.14}} = r \\ \\ \sqrt{10.22} = r$
3.19 ≈ r

So, the radius is approximately equal to 3.19 feet.