To find radius $ r $ use formula:
$$ V = \dfrac{ h ^{ 2 } \cdot r \cdot \pi}{ 3 } $$After substituting $V = 564\, \text{cm}$ and $h = 11\, \text{cm}$ we have:
$$ 564\, \text{cm} = \dfrac{ 11\, \text{cm} ^{ 2 } \cdot r \cdot \pi}{ 3 } $$$$ 564\, \text{cm} \cdot 3 = 11\, \text{cm} ^{ 2 } \cdot r \cdot \pi $$$$ 1692\, \text{cm} = 121\, \text{cm}^2 \cdot r \cdot \pi $$$$ r = \dfrac{ 1692\, \text{cm} }{ 121\, \text{cm}^2 \, \pi} $$$$ r = 4.4511\, \text{cm}^-1 $$