Proposition: 7.23: Divisor of One of Coprime Numbers is Coprime to Other
(Proposition 23 from Book 7 of Euclid's “Elements”)
If two numbers are prime to one another then a number measuring one of them will be prime to the remaining (one).
Modern Formulation
If $A$ and $B$ are coprime and $C$ is a divisor of $A$, then $C$ and $B$ are also coprime.
Table of Contents
Proofs: 1
Mentioned in:
Proofs: 1
Thank you to the contributors under CC BYSA 4.0!
 Github:

 nonGithub:
 @Fitzpatrick
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