Proposition: Prop. 10.031: Constructing Medial Commensurable in Square I

(Proposition 31 from Book 10 of Euclid's “Elements”)

To find two medial (straight lines), commensurable in square only, (and) containing a rational (area), such that the square on the greater is larger than the (square on the) lesser by the (square) on (some straight line) commensurable in length with the greater.

Modern Formulation

(not yet contributed)

Proofs: 1

Proofs: 1

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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",, 2016