Check the picture below.
[tex]\bf \textit{area of a trapezoid}\\\\ A=\cfrac{h(a+b)}{2}~~ \begin{cases} a,b=\stackrel{parallel~sides}{bases}\\ h=height\\[-0.5em] \hrulefill\\ a=12\\ b=15\\ h=16 \end{cases}\implies A=\cfrac{16(12+15)}{2}\implies A=216[/tex]