| ai, | io, | ai, | io. |
| eu, | ua, | en, | ai. |
by the [32. e.]
Therefore the reason of en, unto io , that is of ey, unto
yo, shall be made of the foresaid reasons.
Of the segments of divers right lines, the Arabians have much under the name of The rule of sixe quantities. And the Theoremes of Althindus, concerning this matter, are in many mens hands. And Regiomontanus in his Algorithmus: and Maurolycus upon the 1 p iij. of Menelaus, doe make mention of them; but they containe nothing, which may not, by any man skillfull in Arithmeticke, be performed by the multiplication of proportions. For all those wayes of theirs are no more but speciall examples of that kinde of multiplication.
Of Geometry, the sixt Booke, of a Triangle.
1. Like plaines have a double reason of their homologall sides, and one proportionall meane, out of 20 p vj. and xj. and 18. p viij.
Or thus; Like plaines have the proportion of their correspondent proportionall sides doubled, & one meane proportionall: Hitherto wee have spoken of plaine lines and their affections: Plaine figures and their kindes doe follow in the next place. And first, there is premised a common corollary drawne out of the [24. e. iiij]. because in plaines there are but two dimensions.
2. A plaine surface is either rectilineall or obliquelineall, [or rightlined, or crookedlined. H.]