[tex]\bf \begin{array}{llll}
\textit{volume of a cylinder}\\\\
V=\pi r^2 h
\end{array}\qquad \qquad\qquad
\begin{array}{llll}
\textit{volume of a cone}\\\\
V=\cfrac{\pi r^2 h}{3}\implies \cfrac{1}{3}(\pi r^2 h)
\end{array}[/tex]
notice, the volume of a cylinder with a radius of "r" and a height of "h" is that much, whilst the volume of a cone with the same exact "r" and "h" is, well, one third that of the cylinder's.