Pyramids of the same height with triangular bases are to one another as their bases. Proposition 6 . Pyramids of the same height with polygonal bases are to one another as their bases. Proposition 7 . Any prism with a triangular base is divided into three pyramids equal to one another with triangular bases.
Any pyramid is a third part of the prism with the same base and equal height.
Proposition 8 . Similar pyramids with triangular bases are in triplicate ratio of their corresponding sides. Similar pyramids with polygonal bases are also to one another in triplicate ratio of their corresponding sides. Proposition 9 . Proposition 10 .