based on Cavalieri's Principle, an oblique solid which have the same altitude and cross-sectional areas all the way, is the same volume as one that is not oblique.
[tex]\bf \textit{volume of a cone}\\\\
V=\cfrac{\pi r^2 h}{3}~~
\begin{cases}
r=5\\
h=9
\end{cases}\implies V=\cfrac{\pi (5)^2(9)}{3}\implies V=75\pi [/tex]
