Corollary: Rectangle as a Special Case of a Parallelogram
(related to Proposition: 1.34: Opposite Sides and Opposite Angles of Parallelograms)
If one angle of a parallelogram is a right angle, each of its angles are right angles and it is called a rectangle.

Table of Contents
Proofs: 1
Thank you to the contributors under CC BY-SA 4.0!

- Github:
-

- non-Github:
- @Calahan
- @Casey
References
Adapted from CC BY-SA 3.0 Sources:
- Callahan, Daniel: "Euclid’s 'Elements' Redux" 2014
Adapted from (Public Domain)
- Casey, John: "The First Six Books of the Elements of Euclid"