Plimpton 322, the oldest trigonometric table ever discovered

Australian researchers have worked on what would be the first trigonometric table in history. Found at the beginning of the 20th century, this ancient table has been gradually revealing its secrets!

The table, named Plimpton 322, was acquired in 1922 by the American publisher and philanthropist George Arthur Plimpton. The latter reported that the relic was found a few years earlier in Iraq by Edgar Banks, an American archaeologist who have strongly inspired the famous Indiana Jones character.

Nearly 100 years later, at the end of 2017, a team of archaeologists from the University of New South Wales (Australia) reported a significant breakthrough on the origin and purpose of the tablet. According to the study published in the journal Historia Mathematica – the official journal of the International Commission of History of Mathematics – the researchers have dated the Plimpton table and defined its use.

How does the table work?

Plimpton 322 was used by the Babylonians during antiquity and is composed of 15 lines separated by four columns. It is a base 60 system that has derived integers rather than fractions. According to the leaders of the study, the table was used to study triangles.

However, it is a question of taking into account proportions rather than angles, almost equal proportions of the first line of the table and forming a triangle almost equilateral. The fact is that the more you go to the bottom of the table, the narrower the triangles, because the inclination becomes more important.

What use?

Australian researchers believe that this table is a real ingenuity and that it would have been used to study the field – calculation of slope – to build buildings, including pyramids.

Donald Allen (University of Texas) – questioned by National Geographic – estimates that many mathematical interpretations of the table are equivalent. For the interested party, nothing really suggests that this table was used for trigonometry. On the other hand, the expert considers that the major discovery concerning Plimpton 322 is that the Babylonians seemed to have known the Pythagorean theorem well before the latter had appeared!.

Shakes Gilles

Editor of The Talking Democrat. He enjoys bike riding, kayaking and playing soccer. On a slow weekend, you'll find him with a book by the lake.