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 ...

and is abbreviated to cos. For a given angle Ɵ, cosƟ = adjacent ÷ hypotenuse. This is written as a fraction. Image caption, The opposite divided by the adjacent for each triangle is 3/4 or 6/8.

Sine and cosine are ratios that are defined in the context of a triangle's right angle, and they can be presented according ...