Morley's Trisector Theorem/Dijkstra's Proof/Historical Note

Historical Note on Dijkstra's Proof of Morley's Trisector Theorem

This proof was published by Edsger Wybe Dijkstra on $30$ December $1975$ in an open letter to Ross Honsberger.

As he put it:

the other day I encountered your delightful booklet "Mathematical Gems". On account of Chapter 8, I concluded that you might be interested in the following proof of Morley’s Theorem "The adjacent pairs of the trisectors of a triangle always meet at the vertices of an equilateral triangle." ... I found this proof in the early sixties, but am afraid that I did not publish it.

Sources

• $30$ December $1975$: Open letter from Edsger W. Dijkstra to Ross Honsberger: EWD544