Answer
$r=\dfrac{C}{2\pi}$
This formula gives the radius of a circle where C = circumference of the circle.
Work Step by Step
Divide $2\pi$ on both sides of the equation to obtain:
$\require{cancel}
\dfrac{C}{2\pi} = \dfrac{2\pi{r}}{2\pi}
\\\dfrac{C}{2\pi} = r
\\r=\dfrac{C}{2\pi}$
This formula gives the radius of a circle where C = circumference of the circle.