1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I don't see why you have to put the ((x/2)+ 3)dx next to the equation for a trapezoid. I also don't understand what number would equal x, 4? 2?. Also, the dx, what equation am I supposed to be deriving? .5((B+b)/2)h? that equation doesn't derive.