◀ ▲ ▶Branches / Geometry / Elements-euclid / Book--1-plane-geometry / Corollary: Parallelogram - Defining Property II

Corollary: Parallelogram - Defining Property II

(related to Proposition: 1.34: Opposite Sides and Opposite Angles of Parallelograms)

If both pairs of opposite angles of a 4-sided figure are equal, it is a parallelogram or a rhombus.

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:

1. Callahan, Daniel: "Euclid’s 'Elements' Redux" 2014

Adapted from (Public Domain)

1. Casey, John: "The First Six Books of the Elements of Euclid"