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 51
w CF (31. 1.) parallel toAD or BR; then AF -f CE = AE. But AF= AD.AC = AB AC, because AD = AB;CE = BE.BC = AB BC; and AE = AB«.Therefore AB.AC -f AB.BC = AB^. There-fore, if a straight line, &c. Q. E. D. PROP. III. THEOR. If a straight line be divided into any to parts, the rect-angle contained… … OF GEOMETRY. BOOK 11. 51
Euclid's Elements · Geometry · Trigonometry
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