The area formula for trapezoids is
[tex]A=\frac{(B+b)h}{2}[/tex]Where B = 9 cm, b = 7 cm, and A = 80 cm2. Let's replace these dimensions to find h
[tex]\begin{gathered} 80=\frac{(9+7)\cdot h}{2} \\ 160=16h \\ h=\frac{160}{16} \\ h=10 \end{gathered}[/tex]