To find area $ A $ use formula:
$$ A = \dfrac{ a \cdot a \cdot \sin( \alpha ) }{ 1 } $$After substituting $a = 338\, \text{cm}$, $a = 338\, \text{cm}$ and $\alpha = 36.5^o$ we have:
$$ A = \dfrac{ 338\, \text{cm} \cdot 338\, \text{cm} \cdot \sin( 36.5^o ) }{ 1 } $$ $$ A = \dfrac{ 338\, \text{cm} \cdot 338\, \text{cm} \cdot 0.5948 }{ 1 } $$ $$ A = \dfrac{ 114244\, \text{cm}^2 \cdot 0.5948 }{ 1 } $$ $$ A = \dfrac{ 67954.9344\, \text{cm}^2 }{ 1 } $$ $$ A = 67954.9344\, \text{cm}^2 $$