of pyramides. Now it is required that they be homogeneall or of like kindes; Because a Pentaedrum with an Hexaedrum will not so agree.
This element is a consectary out of the [16 e iiij].
And
9. If they be reciprocall in base and heighth, they are equall.
This is a Consectary out the [18 e iiij].
And
10. If a Prisma be cut by a plaine parallell to his opposite flattes, the segments are as the bases are. 25 p. xj.
The segments are homogeneall because the prismas. Therefore seeing they are of equall heighth (by the heighth I meane of plaine dividing them) they shall be as their bases are: And here the bases are to be taken opposite to the heighth.