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 131
480 ELEMENTS point E. And beeause GH is parallel to EF, one of the sides of thetrian-Ie DEF, DG : GE ;: DH : HF (3. fi.); but DG=A, GE = B,and DH=C; and therefore A : B :.* C : HF. Wherefore to the threeffiven straight lines, A, B, C, a fourth proportional HF is found.Which was to be done. PROP.…
Euclid's Elements · Geometry · Trigonometry
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