so hmm notice the picture below
now if the diameter is 150, the radius is half that, or 75
thus [tex]\bf V_{cylinder}=\pi r^2 h\qquad
\begin{cases}
h=4h\\
r=75
\end{cases}\implies V_{cylinder}=75^2\pi \cdot 4h
\\\\\\
\boxed{V_{cylinder}=22500\pi h}
\\\\\\
V_{cone}=\cfrac{\pi r^2 h}{3}\qquad
\begin{cases}
h=h\\
r=75
\end{cases}\implies \boxed{V_{cone}=1875\pi h}\\\\
-----------------------------\\\\
343000=22500\pi h+2(1875\pi h)\implies 343000=26250\pi h
\\\\\\
\cfrac{343000}{26250\pi }=h[/tex]
and surely, you know how much that is
