1. The problem statement, all variables and given/known data Find the mass of the surface of the triangle with vertice (2,0,0), (0,2,0), (0,0,1) if the density is 4xz 2. Relevant equations 3. The attempt at a solution I know I just need to take the integral of 4xy in the region of the triangle, but how do i set up the integral for the triangle? I am not used to triangles in 3d space, do I need to make a transformation or is there some easier way. I'm not really sure where to start on this one, but once i get the integral set up I supposed its easy.