To find volume $ V $ use formula:
$$ V = \dfrac{ 4 \cdot r^2 \cdot \pi}{ 3 } $$After substituting $ r = 8 $ we have:
$$ V = \dfrac{ 4 \cdot 8^2 \cdot \pi}{ 3 } $$ $$ V = \dfrac{ 4 \cdot 64 \cdot \pi}{ 3 }$$ $$ V = \dfrac{ 256 \cdot \pi}{ 3 }$$ $$ V = \frac{ 256 }{ 3 } \cdot \pi $$