To find height $ h $ use formula:
$$ A = a \cdot h $$After substituting $A = 40.87\, \text{cm}$ and $a = 10.67\, \text{cm}$ we have:
$$ 40.87\, \text{cm} = 10.67\, \text{cm} \cdot h $$$$ h = \dfrac{ 40.87\, \text{cm} }{ 10.67\, \text{cm} } $$$$ h = 3.8304 $$