\begin{enumerate}[label=(\roman*.)]\item For a cone with a circular base of radius $r$ and height $h$, the volume $V=\frac13 \pi r^2 h$.\item For a cylinder with base radius $r$ and height $h$, the volume $V=\pi r^2 h$.\item For sphere with radius $r$, the volume $V=\frac43\pi r^3$.\end{enumerate}