We're going to find the volume of the cylinder using the following equation:
[tex]V=\pi\cdot r^2\cdot h[/tex]Since the radius measures 5 ft, the height measures 12 ft and the problem tells us that we should take pi as 3, we could replace:
[tex]\begin{gathered} V\approx3\cdot(5ft)^2\cdot12ft \\ V\approx3\cdot25ft^2\cdot12ft \\ V\approx900ft^3 \end{gathered}[/tex]Therefore, the volume is approximately 900ft3.