Euclid:Proposition/XI/35/Porism

From ProofWiki
Jump to navigation Jump to search

Proposition

In the words of Euclid:

From this it is manifest that, if there be two equal plane angles, and if there be set up on them elevated straight lines which are equal and contain equal angles with the original straight lines respectively, the perpendiculars drawn from their extremities to the planes in which are the original angles are equal to one another.

(The Elements: Book $\text{XI}$: Proposition $35$ : Porism)


Sources