To find volume $ V $ use formula:
$$ V = \dfrac{ 4 \cdot r^2 \cdot \pi}{ 3 } $$After substituting $ r = 6.5 $ we have:
$$ V = \dfrac{ 4 \cdot 6.5^2 \cdot \pi}{ 3 } $$ $$ V = \dfrac{ 4 \cdot 42.25 \cdot \pi}{ 3 }$$ $$ V = \dfrac{ 169 \cdot \pi}{ 3 }$$ $$ V = 56.3333 \cdot \pi $$