Using the given formula, we solve for r: \(\displaystyle{V}=\pi r^{2}h\)

Divide both sides by \(\pi h\)

\(V/ \pi h=r^{2}\)

Take the square root:

\(r=\sqrt{V/πh}\)

Substitute \(V=160\pi m^{3}\) and \(h=8m\)

\(r=\sqrt{160\pi/\pi(8)}\)

\(r=\sqrt{20}\)

\(r=\sqrt{4 \cdot 5}\)

\(r=2\sqrt{m} ~ 4.5 m\)