
$\mathrm{A}$ trapezium $\mathrm{ABCD}$ has side $\mathrm{AD}$ parallel to $\mathrm{BC}, \angle \mathrm{BAD}=90^{\circ}, \mathrm{BC}=3 \mathrm{~cm}$ and $\mathrm{AD}=8 \mathrm{~cm}$. If the perimeter of this trapezium is $36 \mathrm{~cm}$, then its area, in sq. $\mathrm{cm}$, is