[tex]\bf \textit{volume of a sphere}\\\\ V=\cfrac{4\pi r^3}{3}~~ \begin{cases} r=radius\\ \cline{1-1} V=2,143.57 \end{cases}\implies 2143.57=\cfrac{4\pi r^3}{3}\implies 6430.71=4\pi r^3 \\\\\\ \cfrac{6430.71}{4\pi }=r^3\implies \stackrel{\pi =3.14}{\cfrac{6430.71}{4(3.14) }}=r^3\implies 511.9992\approx r^3 \\\\\\ \sqrt[3]{511.9992}\approx r\implies 7.999996\approx r\implies \stackrel{\textit{rounded up}}{8=r}[/tex]