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 139
tilineal figures which are similar to the same rectili-neal figure, are also similar to one another. Let each of the rectilineal figures A, B be similar to the rectilinealfigure C: Tl»e figure A is similar to the figure B. Because A is similar to C, they are equiangular, and also have theirsides… … are each of them equiangular to C, and have the sides about theequal angles of each of them, and of C, proportionals. Whereforethe recliJineal figures A and B are equiangular (1. Ax. 1.), and havetheir sides about the equal angles proportionals (il. 5.). ThereforeA is similar (def. 1.6.) to B. Q.…
Euclid's Elements · Geometry · Trigonometry
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