To find radius $ r $ use formula:

$$ V = \dfrac{ 4 \cdot r^3 \cdot \pi }{ 3 }$$

After substituting $V = 1.0821\, \text{m}^2$ we have:

$$ 1.0821\, \text{m}^2 = \dfrac{ 4 \cdot r^3 \cdot \pi }{ 3 }$$ $$ 1.0821\, \text{m}^2 \cdot 3 = 4 \cdot r^3 \cdot \pi $$ $$ 3.2463\, \text{m}^2 = 4 \cdot r^3 \cdot \pi $$ $$ r^3 \cdot \pi = \dfrac{ 3.2463\, \text{m}^2 }{ 4 } $$ $$ r^3 \cdot \pi = 0.8116\, \text{m}^2 $$ $$ r = \sqrt[3]{ \frac{ 0.8116\, \text{m}^2 }{\pi} } $$ $$ r \approx 0.6369\, \text{m} $$

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