Elements of geometry : containing the first six books of Euclid, with a supplement on the quadrature of the circle, and the geometry of solids : to which are added, Elements of plane and spherical geometry (1826)
Playfair, John, 1748-1819, Euclid · Philadelphia : Marot & Walter · leaf 141
o PR: and because as AB toCD, so is EF to Pil, and because PR is equal to GH, AB is to CD, asEF to GH. If therefore (our straight lines, &c. Q. E. D, PROP. Xilll. THEOR. Equiangular parallelogramsIrkvcl^ one another the ratiowhich is compounded of the i^ios of their sides. Let AC, CF be… … 140 ELEMENTS Let BC, CG be placed ia a straight line; therefore DC and CE arealso in a straight, line (14. 1.); complete the parallelogram DG; and,taking any straight line K, make (13. 6.) as BC to CG, so K to L;and as DC toCE, so make (12. 6.) L to M: therefore the ratios of Kto L, and L to M, are…
Euclid's Elements · Geometry · Trigonometry
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