Before Pythagoras:
The Culture of Old Babylonian Mathematics
Extended dates: November 12, 2010 - January 23, 2011
Tablet illustrating Pythagoras' Theorem and the square root of 2
YBC 7289 (obverse).
Image by West Semitic
Research. All rights reserved.
YBC 7289 (reverse).
Image by West Semitic
Research. All rights reserved.
Yale Babylonian Collection YBC 7289
Old Babylonian Period (19th-17th century BCE), southern
Mesopotamia?
Acquired by the Yale Babylonian Collection by
1944
This famous tablet, one of few to consist entirely of a geometrical diagram, is a graphic witness that Babylonian scribes knew Pythagoras' Theorem and possessed a method of calculating accurate estimates of square roots. On the obverse, the scribe has drawn a square and its diagonals.
According to Pythagoras' Theorem the length of the diagonal is the length of the side multiplied by the square root of 2. An accurate approximation of this quantity in sexagesimal notation is written along one diagonal. One side is labelled with its length, and the product of this number by the square root of 2 is also written along the diagonal.