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 96
; therefore also C A is equal to CD, and the angle CDAequal (3. 1.) to the angle DAC; therefore the angles CDA, DAC to-gether, are double of the angle DAC; but BCD is equal to the an-gles CDA, DAC (32.1.); therefore also BCD is double of DAC.But BCD is equal to each of the angles BDA, DBA, and… … «• -teLBMENTS « Cor. 1. The aBajle BAD is the fifth part of tw» T\^ht angles.For since >^hc1i of the angles ABD and ADB is equ:\l to twice theans^le BAD, they are together equal to four times BAD, and there-fore all the tiiree angles ABD, ADB, BAD, taken together, areequal to five times the…
Euclid's Elements · Geometry · Trigonometry
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