1. The problem statement, all variables and given/known data http://3.1m.yt/J986z5A.jpg 2. Relevant equations 3. The attempt at a solution I don't know if this is a cross section or if I should draw it. Could you give me a any other example or hint a bout this exercise? I think it can be a triangle, but I am not sure. i don't know how to add the lines or draw the section.