For this question you have to solve the equation backwards. A = 1/2 x (b1 + b2) x h In order to get rid of the 1/2 (since it's division) multiply each side by 2 now we have: 2A = (b1 + b2) x h Now do the same to the get rid of the (b1 + b2) (divide each side by it) 2A/(b1 + b2) = h
