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Proposition: 4.09: Circumscribing Circle about Square

(Proposition 9 from Book 4 of Euclid's “Elements”)

To circumscribe a circle about a given square.

• Let $ABCD$ be the given square.
• So it is required to circumscribe a circle about square $ABCD$.

Modern Formulation

It is possible to circumscribe a circle about a given square.

Table of Contents

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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