Proposition: Prop. 10.068: Straight Line Commensurable with Major Straight Line is Major
(Proposition 68 from Book 10 of Euclid's “Elements”)
A (straight line) commensurable (in length) with a major (straight line) is itself also major.
* Let $AB$ be a major (straight line), and let $CD$ be commensurable (in length) with $AB$.
* I say that $CD$ is a major (straight line).
Modern Formulation
(not yet contributed)
Table of Contents
Proofs: 1
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References
Adapted from (subject to copyright, with kind permission)
 Fitzpatrick, Richard: Euclid's "Elements of Geometry"
Adapted from CC BYSA 3.0 Sources:
 Prime.mover and others: "Pr∞fWiki", https://proofwiki.org/wiki/Main_Page, 2016