Answer :
[tex]\begin{gathered} \text{The volume is } \\ V=h\cdot A \\ \text{ where h is the height and the area is the basis' area} \\ 8478=\pi(15)^2h \\ \frac{8474}{225\pi}=h \\ h=11.988\ldots\text{ } \\ h\approx12\text{ inches} \end{gathered}[/tex]