T H E E L E M E N T S |
Book III Proposition 20 | |
For let AE be joined and drawn through to F. Then, since EA is equal to EB, the angle EAB is also equal to the angle EBA; [I.5] therefore the angles EAB, EBA are double of the angle EAB. But the angle BEF is equal to the angles EAB, EBA; [I.32] therefore the angle BEF is also double of the angle EAB. |
||
Previous Page Return to Propositions Next Page |