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 217
e C, (Def. 4.); therefore CB : BA : : R : sin. C. Also, because EG touches the circle in E, CEGis a right angle, c and therefore equal to the angle BAC; and since the angle at C is common to the triangles CB A, CGE, these triangles are equiangular, wherefore CA : AB :: CE : EG ; but CE is the… … PLANE TRIGONOMETRY. 2i: tHe angle C (def. 7.), and the triangles CGE, CBA being equiangular,CA : CB : : CE : CGf,that is, CA : CB : : R : sec. C. Cor. 2. If the analogies in this proposition, and in the above eo-rollary be arithmetically expressed, making the radius==l, they give sin. C= AH; tan.…
Euclid's Elements · Geometry · Trigonometry
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