[tex]\bf \begin{array}{llll} \textit{volume of a sphere}\\\\ V=\cfrac{4\pi r^3}{3}~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=10 \end{cases} \\\\\\ V=\cfrac{4\pi 10^3}{3}\implies V=\cfrac{4000\pi }{3} \end{array}~\hfill \begin{array}{llll} \textit{volume of a sphere}\\\\ V=\cfrac{4\pi r^3}{3}~~ \begin{cases} r=radius\\[-0.5em] \hrulefill\\ r=20 \end{cases} \\\\\\ V=\cfrac{4\pi 20^3}{3}\implies V=\cfrac{32000\pi }{3} \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}[/tex]
[tex]\bf \cfrac{32000\pi }{3}-\cfrac{4000\pi }{3}\implies \cfrac{32000\pi -4000\pi }{3}\implies \cfrac{28000\pi }{3}\qquad \approx\qquad 29321.5[/tex]
