To find radius $ r $ use formula:
$$ V = r ^{ 2 } \cdot h \cdot \pi$$After substituting $ V = 4100 $ and $ h = 19 $ we have:
$$ 4100 = 19 \cdot r ^{ 2 } \cdot \pi $$$$ r ^{ 2 } = \dfrac{ 4100}{ 19 \, \pi } $$$$ r ^{ 2 } = 1305.0716 $$$$ r = \sqrt{ 1305.0716 } $$$$ r = 36.1258 $$