Posted by: Alexandre Borovik | July 24, 2008

## Thales of Miletus

I am lecturing at the Nesin Mathematics Village. There are no lectures today; a colleague organised a tour of Miletus, ruins of an ancient city where Thales, perhaps the first mathematician known to us by name, was born and lived. I am reading a fascinating old book Aegean Turkey by George E. Bean. His style is charming:

Thales also, we read, was the first man to succeed in inscribing a right-angled triangle in a circle; in celebration of this he sacrificed an ox — which means in effect that he stood himself a good dinner.

Mathematicians should definitely keep alive the tradition of celebrating a new theorem with a good dinner.

By the way, Bean makes the following remark regarding the result that, in Thales opinion, deserved a dinner of an ox:

There is something wrong here. The least mathematically-minded can inscribe a right-angled triangel in a circle. Unless we should read `equilateral triangle’, the meaning is probably that Thales first proved that a triangle inscribed in a semicircle is right-angled.

Comments anyone?

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## Responses

1. Certainly “Thales’ Theorem” is that the angle in a semicircle is right. Inscribing a right triangle in a circle could, of course, be done without this result – provided you can construct a right angle. Given that he’s also credited with the results that the diameter bisects a circle and that isosceles triangles have equal base angles, it may not even be safe to assume that! These were basic days.

Apparently he was easily distracted by lissom young girls (or boys), since Wikipedia claims he died of dehydration while watching a gymnastics contest. I’m with him (and you) about the dinners, though.