Proposition: Prop. 8.23: If First of Four Numbers in Geometric Progression is Cube then Fourth is Cube

(Proposition 23 from Book 8 of Euclid's “Elements”)

If four numbers are in continued proportion, and the first is cube, then the fourth will also be cube.

fig23e

Modern Formulation

(not yet contributed)

Proofs: 1

Proofs: 1 2 3 4 5 6 7


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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