Proof: By Euclid
(related to Corollary: 6.20: Similar Polygons are Composed of Similar Triangles)
It follows from Prop 6.19 and the fact that every rectilinear figure can be triangulated.
∎
Thank you to the contributors under CC BY-SA 4.0!
![](https://github.com/bookofproofs/bookofproofs.github.io/blob/main/_sources/_assets/images/calendar-black.png?raw=true)
- Github:
-
![bookofproofs](https://github.com/bookofproofs.png?size=32)
References
Bibliography
- Byrne, O.: "The First Six Books of the Elements of Euclid, in Which Coloured Diagrams and Symbols are used Instead of Letters", London William Pickering, 1847