1. The problem statement, all variables and given/known data A dam has a rectangular base 1500 meters long and 140 meters wide. Its cross-section is shown in the figure. (The Grand Coulee Dam in Washington state is roughly this size.) By slicing horizontally, set up and evaluate a definite integral giving the volume of material used to build this dam. The height at the top is 10m, bottom is 140m, and the height is 130m. 2. Relevant equations I tried to use similar triangles but I really have no idea how to do this. Any suggestions? 3. The attempt at a solution 130-h / 130 = w/140 w= 130-(h/130) but integrating this and multiplying by the base (1500) gives the wrong answer.