For Circles are like plaines. And their homologall sides are their diameters, as was foretold at the [24 e iiij]. And therefore by the [1 e vj], they are one to another, as the quadrates of their diameters are one to another, which indeed is the double reason of their homologall sides. As here the Circle aei, is unto the Circle ouy as 25, is unto 16, which are
the quadrates of their Dieameters, 5 and 4.
Therefore
3. The Diameters are, as their peripheries Pappus, 5 l. xj, and 26th. 18.
As here thou seest in ae, and io.
4. Circular Geometry is either in Lines, or in the segments of a Circle.
This partition of the subject matters howsoever is taken for the distinguishing and severing with some light a matter somewhat confused; And indeed concerning lines, the consideration of secants is here the foremost, and first of Inscripts.
5. If a right line be bounded by two points in the periphery, it shall fall within the Circle. 2 p iij.