Check the picture below.
[tex]\bf \textit{volume of a cylinder}\\\\ V=\pi r^2 h~~ \begin{cases} r=radius\\ h=height\\[-0.5em] \hrulefill\\ h = 6\\ r=3 \end{cases}\implies V=\pi (3)^2(6)\implies \stackrel{in^3}{V=54\pi}[/tex]