# Tangent

(1) In trigonometry, the tangent of an angle is the ratio of the length of a given angle's opposite side to the length of the angle's adjacent side in a right triangle. (2) In geometry, two figures are said to be tangent to one another if they "just touch".

Tangent is a high school-level concept that would be first encountered in a trigonometry course. It is listed in the California State Standards for Trigonometry.

### Prerequisites

Right Triangle: | A right triangle is a triangle that has a right angle. The Pythagorean Theorem is a relationship among the sides of a right triangle. |

Trigonometry: | Trigonometry is the study of angles and of the angular relationships of planar and three-dimensional figures. |