Key points Trigonometry close trigonometryThe study of sides and angles in triangles. can be used to find a missing side in a right-angled triangle when another side and an angle are known.

A 3,700-year old Babylonian clay tablet reveals an ancient method of constructing right-angled triangles that makes it the world’s oldest and most accurate trigonometric table.

The Plimpton 322 tablet The ancient Babylonians understood key concepts in geometry, including how to make precise right-angled triangles. They used this mathematical know-how to divide up ...