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\\ h=6\\ a=6\\ b=12 \end{cases} \\\\\\ A=\cfrac{6(6+12)}{2}\implies A=3(18)\implies A=54[/tex]
