[tex]\textit{area of a trapezoid}\\\\ A=\cfrac{h(a+b)}{2}~~ \begin{cases} h~~=height\\ a,b=\stackrel{parallel~sides}{bases}\\[-0.5em] \hrulefill\\ A=30.6\\ a=3.2\\ b = 7 \end{cases}\implies 30.6=\cfrac{h(3.2+7)}{2} \\\\\\ 61.2=h(3.2+7)\implies 61.2=10.2h\implies \cfrac{61.2}{10.2}=h\implies 6=h[/tex]
