Return to my Egyptology pages
Go to my home page

The 3-4-5 Right Triangle In Ancient Egypt

© Copyright 1999, Jim Loy

I have read, and heard, something like the following:

The ancient Egyptians obviously knew of the Pythagorean Theorem, way back before Pythagoras, because knotted ropes have been found which could be used to make a 3-4-5 right triangle. And they used these ropes to make right angles, for land boundaries.

A few comments must be made, about that:

1. It is extremely difficult to tie equal spaced knots. It certainly can be done. But, I have tried, with little success.
2. How big a rope would you need to survey land? A rope of manageable size seems almost too small for making a right angle of the necessary accuracy.
3. Ropes stretch. You would have to be careful to have the same tension in all three directions.
4. There are much better ways to make a right angle. Carpenters and architects use a square of some sort (L- or T-shaped). Geometry students bisect a straight angle.
5. People who study mathematical Egyptology say that there is no documentation for the claim, at all.

It would seem to be a baseless rumor.

One further comment: A person can easily guess that a 3-4-5 triangle is a right triangle. Amateur mathematics is often experimental. And, people often make guesses like this. You would start with a 1-2-2 triangle, and see that it is not even close. A 3-4-5 triangle would come up fairly soon. And, guessing that a 3-4-5 triangle is a right triangle does not imply the Pythagorean Theorem.

See The Pythagorean Theorem.

Return to my Egyptology pages
Go to my home page