Euclid:Proposition/I/27

Proposition

In the words of Euclid:

If a straight line falling on two straight lines make the alternate angles equal to one another, the straight lines will be parallel to one another.

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


Sources

  • 1926: Sir Thomas L. Heath: Euclid: The Thirteen Books of The Elements: Volume 1 (2nd ed.) ... (previous) ... (next): Book $\text{I}$. Propositions
This article is issued from ProofWiki. The text is available under Creative Commons Attribution-ShareAlike License unless otherwise noted. Additional terms may apply for the media files.