SATMathematics Practice Test 1

The volume of a cylinder is $\mathit{\pi }{\mathit{r}}^2\mathit{h}$, where r is the radius of the base of the cylinder and h is the height of the cylinder.
Since the storage silo is a cylinder with volume $72\mathit{\pi }$ cubic yards and height 8 yards, it is true that $72\mathit{\pi }=\mathit{\pi }{\mathit{r}}^2\left(8\right)$,where r is the radius of the base of the cylinder, in yards.
Dividing both sides of $72\mathit{\pi }=\mathit{\pi }{\mathit{r}}^2\left(8\right)$ by $8\mathit{\pi }$ gives ${\mathit{r}}^2=9$,and so the radius of base of the cylinder is 3 yards.
Therefore, the diameter of the base of the cylinder is 6 yards.
Therefore, the diameter of the base of the cylinder is 6 yards.