The tablet, Plimpton 322, was discovered in the 1920s by J. Edgar Banks, who served as the inspiration for Indiana Jones. Researchers have known for years that the tablet depicts a chart of triangle side measurements that follow Pythagorean ratios (think a2 + b2 = c2), but no one knew why the Babylonians decided to record those numbers, reports Ron Cowen for Science.

**How it works:** Modern trigonometry is based on approximations, in part because our mathematics is a base-10 system. This means our math requires lots of decimal points or rounding, like when you divide 1 by 3. But the Babylonians used a system based around 60s, like a modern clock. It made division easier for them, just like we can easily divide an hour by 1, 5, 10, 12 and others without using decimals.

**What it means:** This math system let them describe triangles using a precise ratio of sides. The researchers think it could have been used in construction, allowing them to use the size of a pyramid base and the height of a pyramid to calculate the length of the sloped portion.

**Not so fast:** Although exciting, this interpretation of the iconic tablet isn't set in stone. Half of the relic is missing — the half researchers speculate has the solutions to the trigonometry problems and would help determine if this tablet isn't just a list of Pythagorean triangles, but an actual tool that uses a novel kind of trigonometry to calculate them.

"Apart from the column headings, the tablet just consists of columns of numbers, and this invites a great deal of purely mathematical speculation," Duncan Melville, who studies Mesopotamian mathematics, told National Geographic.

**Go deeper:** Watch this video, produced by University New South Whales in Australia, to see the tablet and read this article The Conversation by the authors of the paper.