Question

If the surface area of a sphere is 900 pi, then its radius is

Answer 1

The surface area of a sphere is computed as follows:

$A=4\pi r^2$

where r is the radius. Substituting with A = 900π

$\begin{gathered} 900\pi=4\pi r^2 \\ \frac{900\pi}{4\pi}=\frac{4\pi r^2}{4\pi} \\ 225=r^2 \\ \sqrt[]{225}=r \\ 15=r \end{gathered}$