A=½ (a+b) h solve for h

The object is to get everything except for "h" on one side of the equation.

The equation says that everything on the right side is being multiplied by 1/2.

What do we have to multiply times 1/2 to get 1? The answer is 2.

So multiply both sides by 2 to get rid of the fraction.

2A = (a+b) h

Now we are multiplying h times (a+b) so to get rid of (a+b) we have to divide both sides by that term.

(a+b) / (a+b) is 1

So you are left with: 2A / (a+b) = h

Done!