Answer
$h=\frac{2A}{b}$; 8cm
Work Step by Step
$A=\frac{1}{2}bh$
Divide each side by $b$
$\frac{A}{b}=\frac{1}{2}h$
To get $h$ by itself, we have to pultiply by the reciprical of $\frac{1}{2}$ (which is 2).
$h=\frac{2A}{b}$
For the second part of the problem, plug in the numbers given.
$h= \frac{2\times28cm^{2}}{7cm}$
Simplify the fraction
$h= \frac{2\times4cm^{2}}{1cm}$
Solve the equation
$h=8cm$
