Solve for the formula for the indicated variable. Solve A=1/2bh for b.

b = 2A/h

The way you would get this is first by clearing the fraction. So in order to clear the fraction, you have to multiply the equation by the denominator.

2(A = 1/2bh)

2A = 1bh

2A = bh

Then you have to isolate the variable. So you'd divide bh by h in order to get b by itself. So you'd end up with:

2A/h = bh/h

2A/h = b