1. ## geometry homework

how many cubic inches of material are needed for a solid rubber ball with a diameter of 3 inches?

$\displaystyle V=\frac{4}{3} \pi r^3$
$\displaystyle D=2r$
so $\displaystyle r=\frac{3}{2}in$
$\displaystyle V==\frac{4}{3} \pi \left( \frac{3}{2}in \right)^3=\frac{4 \pi}{3}\frac{27}{8}in^3 =\frac{9\pi}{2} in^3$