# Tangent (of an angle)

The tangent of an angle is the trigonometric ratio between the adjacent side and the opposite side of a right triangle containing that angle.

abbreviated as "tan"

Example:

In the triangle shown,

and .

The tangent ratio is the same regardless of the size of the right triangle. So, it is often easiest to consider a right triangle with a hypotenuse of length 1.

The tangent ratio can also be thought of as a function, which takes different values depending on the measure of the angle. You can measure an angle in degrees or radians

The reciprocal of the tangent ratio is known as cotangent ratio of an angle, abbreviated as "cot".

That is,

In the above example, and .