The table of trigonometric values was made more than a thousand years before math historians thought trigonometry was invented.

In one of your math classes, you might have been taught that geometry and trigonometry were products of the ancient Greeks. That’s not entirely accurate, as a new discovery proves that both were invented by the Babylonians a thousand years earlier.

Researchers at UNSW Sydney have been studying an ancient Babylonian tablet, and they believe they’ve finally figured out what it’s for. The tablet, known as Plimpton 322, was previously identified as a table filled with sets of Pythagorean triples, but nobody knew its purpose was anything more than an educational tool.

Pythagorean triples are sets of numbers that correspond to the sides of right triangles. They’re numbers that work inside the Pythagorean theorem, a²+b²=c². Previously, researchers thought that Plimpton 322 might be some sort of teaching aid for the simply geometric equation, but the UNSW Sydney team believes it’s much more important.

According to the researchers, Plimpton 322 is a trig table, similar to the ones seen in every high school math textbook, except Plimpton 322 uses triangles instead of circles and angles. The researchers believe that Plimpton 322 could have been used in surveying and construction, planning large projects like palaces and pyramids.

The ancient Babylonians had an advantage over our current counting system because they use base-60, instead of the base-10 system that we use. While we count in powers of ten, like hundreds, thousands, and so on, the Babylonians counted in powers of 60. There are a lot more ways multiples of 60 can be divided into fractions, which makes trigonometry much easier.

The researchers believe that modern mathematics has a lot to learn from the simplicity and accuracy of Babylonian trigonometry. This discovery will not only rewrite the history textbooks, but it might rewrite some math textbooks as well.

Source: UNSW Sydney