Euclid:Proposition/I/32

From ProofWiki
Jump to navigation Jump to search

Proposition

In the words of Euclid:

In any triangle, if one of the sides be produced, the exterior angle is equal to the two interior and opposite angles, and the three interior angles of the triangle are equal to two right angles.

(The Elements: Book $\text{I}$: Proposition $32$)


Sources