To find volume $ V $ use formula:
$$ V = \dfrac{ a ^{ 2 } \cdot h }{ 3 } $$After substituting $a = 10\, \text{cm}$ and $h = 10\, \text{cm}$ we have:
$$ V = \dfrac{ 100\, \text{cm}^2 \cdot 10\, \text{cm} }{ 3 }$$$$ V = \dfrac{ 1000\, \text{cm}^3 }{ 3 } $$$$ V = \frac{ 1000 }{ 3 }\, \text{cm}^3 $$