Who Made Quod Erat Demonstrandum?

Euclid used the Greek original of Quod Erat Faciendum (Q.E.F.) to close propositions that were not proofs of theorems, but constructions of geometric objects. For example, Euclid's first proposition showing how to construct an equilateral triangle, given one side, is concluded this way.

Which symbol represents quod erat demonstrandum?

In mathematics, the tombstone, halmos, end-of-proof, or Q.E.D. symbol "∎" (or "□") is a symbol used to denote the end of a proof, in place of the traditional abbreviation "Q.E.D." for the Latin phrase "quod erat demonstrandum".

Where did QED come from?

The Latin quod erat demonstrandum literally means “what was to be demonstrated.” It is actually a transliteration of a phrase ancient Greek mathematicians placed at the end of logical proofs—a kind of stamp that says “I proved what I set out to. Usage for the abbreviation Q.E.D. is found from the 17th century.

Chloe Bennett

Chloe Bennett

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Chloe Bennett explores the intersection of pop culture, streaming entertainment, digital trends, and contemporary lifestyle. Her weekly commentary reaches thousands of culture enthusiasts.