T H E E L E M E N T S |
Book I Proposition 20 | |
Then, since AD is equal to AC, 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. |
||
Previous Page Return to Propositions Next Page |