To find area $ A $ use formula:
$$ A = a \cdot h $$After substituting $a = 3.5\, \text{cm}$ and $h = 2.5\, \text{cm}$ we have:
$$ A = 3.5\, \text{cm} \cdot 2.5\, \text{cm} $$$$ A = 3.5\, \text{cm} \cdot 2.5\, \text{cm} $$$$ A = 8.75\, \text{cm}^2 $$