Proposition: Prop. 10.019: Product of Rational Numbers is Rational

Euclid's Formulation

The rectangle contained by rational straight lines (which are) commensurable in length is rational.

fig019e

Modern Formulation

(not yet contributed)

Proofs: 1

Proofs: 1 2 3 4 5 6 7 8 9


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References

Adapted from (subject to copyright, with kind permission)

  1. Fitzpatrick, Richard: Euclid's "Elements of Geometry"

Adapted from CC BY-SA 3.0 Sources:

  1. Prime.mover and others: "Pr∞fWiki", https://proofwiki.org/wiki/Main_Page, 2016