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 154
rectangles BA.AB, CA.AD are equal. PROP. K. THEOR. If from any angle of a triangle a perpendicular be drawnto the opposite side or base; the rectangle contained bythe sum and difference of the other two sides, is equal tothe rectangle contained by the sum and difference of thesegments, into which… … From A as a centre with the radius AC, the pjreater of the twosides, describe Ihe circle CFG: produce AB to meet the circumfer-ence in E and F, and CB to meet it in G. Then because AP=AC,BF=AB+AC, the sum of the sides; and since AE=AC, BE=AC,—AB=lhe difference of the sides. Also, because AD drawn…
Euclid's Elements · Geometry · Trigonometry
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