Al-Khwarizmi · Mathematics

Completing the Square

The geometric heart of Al-Khwarizmi’s method - how literally building a square out of an equation turns a recipe into a proof, and reveals why the quadratic formula works.

What you'll be able to recall

You learned how Al-Khwarizmi proves his solution recipes geometrically by ‘completing the square’ - attaching rectangles to a square and filling in the missing corners. Explain how this geometric construction justifies the algebraic procedure and connects to the quadratic formula.

Leads to Euclid.

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