Revise trigonometric ratios of sine, cosine and tangent and calculate angles in right-angled triangles with this Bitesize GCSE Maths Edexcel guide.

Classical trigonometry calls the separation between two lines an "angle", which is the length of a circular arc between two lines.

The mathematical study of triangles has just got a whole lot simpler, according to a researcher who says his new theory of trigonometry is easier to use and more accurate.

Calculating the area of a triangle using trigonometry Trigonometry can be used to find the area of a triangle when you know the length of two sides and the included angle.