[tex]\bf \begin{array}{llll}
\textit{volume of a cone}\\\\
V=\cfrac{\pi r^2 h}{3}
\end{array}\qquad \qquad
\begin{array}{llll}
\textit{volume of a cylinder}\\\\
V=\pi r^2 h\implies V=3\left( \cfrac{\pi r^2 h}{3} \right)
\end{array}[/tex]
so, notice, the volume of a cylinder, with the same "r"adius and thus the same base, and the same "h"eight, is 3 times as large as that of the cone's.
so if the cone has a volume of 20π, the cylinder's is three times that much.
