Answer
$h = \frac{2A}{b}$
Work Step by Step
Our goal is to isolate h. To do this we will divide both sides by .5, which is the same as multiplying both sides by 2, and then divide both sides by b:
A = .5bh
2A = bh
$\frac{2A}{b} = h$
$h = \frac{2A}{b}$