Show that the volume of a general cone (Figure 20) is 5 Ah, where A is the

Question:

Show that the volume of a general cone (Figure 20) is 5 Ah, where A is the area of the base and h is the height. Use this result to give the formula for the volume of
(a) A right circular cone of radius r and height h
(b) A regular tetrahedron with edge length r.