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the angle ADC is also equal to the angle ACD; [1.5]
therefore
the angle BCD is greater than the angle ADC. [C.N.5]
And, since BCD is a triangle having the angle BCD greater than the angle BDC, and the greater angle is subtended by the greater side, [1.19] therefore
BD is greater than BC;
But
AD is equal to AC;
therefore
BA, AC are greater than BC.
