Answer
$A = \frac{C^2}{4\pi}$
Work Step by Step
Area of a circle is $A = \pi r^2$
Circumference of a circle is $C = 2\pi r$
In terms of circumference, solve of r in the circumference of a circle formula and substitute the r into the Area of a circle formula
$\frac {C}{2\pi} = r$
$A = \pi {(\frac{C}{2\pi})}^2$
$A = \frac{C^2}{4\pi}$
