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Corollary: Parallelogram - Defining Property I

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

If both pairs of opposite sides of a 4-sided figure are equal in length, it is a parallelogram.

Table of Contents

Proofs: 1

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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"