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 .
Any cone is a third part of the cylinder with the same base and equal height.
Proposition 11 . Cones and cylinders of the same height are to one another as their bases. Proposition 12 . Similar cones and cylinders are to one another in triplicate ratio of the diameters of their bases. Proposition 13 .