Learn about three trigonometric ratios in similar right-angled triangles with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

"Our research reveals that Plimpton 322 describes the shapes of right-angle triangles using a novel kind of trigonometry based on ratios, not angles and circles," says Mansfield.

A trigonometric table allows you to use one known ratio of the sides of a right-angle triangle to determine the other two unknown ratios.

Its 15 rows describe a sequence of 15 right-angle triangles, which are steadily decreasing in inclination. Also, the left-hand edge of the tablet is broken, meaning parts of Plimpton 322 are missing.

A 3,700-year-old Babylonian clay tablet discovered by the real Indiana Jones has been revealed as the world’s oldest — and most accurate — trigonometric table. Mathematicians believe that the… ...