Question

A circle has an area of 80 square centimeters. Which answer is closest to the measure if its radius?

Answer 1

$\bf \textit{area of a circle}\\\\ A=\pi r^2~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ A=80 \end{cases}\implies 80=\pi r^2\implies \cfrac{80}{\pi }=r^2 \\\\\\ \sqrt{\cfrac{80}{\pi }}=r\implies 5.04627\approx r$