The trigonometric ratios sine, cosine and tangent are used to calculate angles and sides in right angled triangles. We are now going to extend trigonometry beyond right angled triangles and use it ...

Learn how to find the angles in right-angled triangles with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

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.