Chapter 11.5, Problem 7WE

To determine

To Find: The radius and circumference.

Answer to Problem 7WE

  $r=5units$

  $C=10\pi units$

Explanation of Solution

Given: $A=25\pi$

Area of circle

  $\begin{array}{l}A=\pi r^2\\ $ 25\pi =\pi {(r)}^2$r^2=\frac{25\pi }{\pi }\\ r^2=25\\ r=5units\end{array}$

Circumference of a circle

  $\begin{array}{l}C=2\pi r\\ C=2\pi (5)\\ C=10\pi units\end{array}$