The volume is length * width * height. Length * width is 4 * 5 or 20, so we have that 20 * height = 200. Divide by 20 to get height = 10.
The answer would be 9, because you have the 3 edges along the rectangles, and then 3 edges each for the triangles. So 3 + 3 + 3 = 9. I hope this helps!
