\(\bf V=\pi r^2 h
\\\\\\
\textit{now, we change "r" to }\frac{1}{3}r\to \frac{r}{3}
\\\\\\
V=\pi \left( \frac{r}{3} \right)^2 h\implies V=\pi \cdot \cfrac{r^2}{3^2}\cdot h\implies V=\cfrac{\pi r^2 h}{9}\)
the new tanks only hold 1/9 th of the original tanks only
