ABCDEFGH is a rectangular prism with CD = 5, AD = 6, and AE = 8. Find the volume of tetrahedron ABCD.
picture: https://docs.google.com/document/d/1hegf5RxwIpDmmHgV4Q4RMiPwmeOvlzYMTLivVCiJMZ8/edit
The volume of tetrahedron ABCD is 1/2*5*6*8 = 120.
ABCD is a rectangle.
The volume of tetrahedron ABCF = (5 * 6 * 8) / 6 = 40 cubic units