# Sides of an angle

The sides of an angle refer to the two rays or line segments that form the angle. In the figure below, rays BA and BC are the sides of angle ABC.

An angle is formed by rotating a ray around its endpoint. The initial side of an angle is the beginning position of the ray, and the terminal side is the position of the ray after it is rotated.

## Characteristics of the sides of angles

The interior of an angle is the set of all points between the two sides that form the angle.

An angle can be named by its sides or by its interior.

Adjacent angles are two angles that have a common side.