The elements of Euclid for the use of schools and colleges; comprising the first six books and portions of the eleventh and twelfth books; (1903)
Euclid, Todhunter, I. (Isaac), 1820-1884, ed. edt, Simson, Robert, 1687-1768, ed. edt · London; New York, Macmillan · leaf 291
BOOK VI. G. 279 Proposition C. Theorem. If from the vertical angle of a triangle a straight line he drawnperpendicular to the base, the rectangle contained hy the sides of thetriangle is equal to the rectangle contained by the perpendicular andthe diameter of the circle described about the… … E Construction. Describe the circle ACB about the triangle; [IV. 5.draw the diameter AE, and join EC. Proof. Because the right angle BDA = the ^ECA in a semi circle ; [III. 31. and the z.ABD = the Z.AEC in the same segment; [III. 21..-. the AABD is equiangular to the A^EC; .-. BA: AD ::EA : AC;…
Euclid's Elements · Geometry · Mathematics, Greek
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