Proposition: 4.02: Inscribing in Circle Triangle Equiangular with Given Angles

Euclid's Formulation

To inscribe a triangle, equiangular with a given triangle, in a given circle. * Let $ABC$ be the given circle, and $DEF$ the given triangle. * So it is required to inscribe a triangle, equiangular with triangle $DEF$, in circle $ABC$.


Modern Formulation

It is possible to inscribe a triangle with given angles into a circle.

Proofs: 1

Proofs: 1 2 3 4
Propositions: 5
Sections: 6

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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