Tanks A and B are each in the shape of a right circular cylinder. The interior of tank A has a height of 10 meters and a circumference of 8 meters, and the interior of tank B has a height of 8 meters and a circumference of 10 meters. The capacity of tank A is what percent of the capacity of tank B ?

circumference of A = $2\mathrm{\pi r}$ = 8 => so r = $\frac{4}{\pi }$
volume = $\pi \times \frac{4}{\pi }2\times 10$ = $\frac{160}{\pi }$
circumference of B =  $2\mathrm{\pi r}$   = 10 => so r =  $\frac{5}{\pi }$
volume = $\pi \times \frac{5}{\pi }2\times 8$ =   $\frac{200}{\pi }$
so ratio of capacities = 160/200 = 0.8
so capacity of A will be 80% of the capacity of B.