Book I Propositions

This page will eventually contain all the propositions from Book 1. Rather than regurgitate Book 1 itself, of which there are 100s if not 1000s of copies online, the prepositions on this page will be written in a more modern language with perhaps more understandable titles. Once complete, a free Pdf will be available for download.

For those who want the original text, I recommend the page by David Joyce. 

Proposition 1: How to Draw an Equilateral Triangle

Proposition 2: Copying a Line Segment to Another Location

Proposition 3: Reducing the Size of a Line to a Certain Length

Proposition 4: Side-Angle-Side (SAS) Triangle Theorem 

Proposition 5: Base Angles of an Isosceles Triangle are Equal 

Proposition 6: Equal Angles Implies Equal Opposite Sides 

Proposition 8:  Side-Side-Side (SSS) Theorem 

Proposition 9: Dividing an Angle into Two Parts 

Proposition 10: Find the Middle of a Line Segment 

Proposition 11: Drawing a Perpendicular Line 

Proposition 12: Draw a Perpendicular from a Different Point 

Proposition 13: Adjacent Angles on a Straight Line Add to 180 Degrees

Proposition 14: If Adjacent Angles Add to 180 Degrees, the Lines Are Straight