Set of points on a line that are located on the same side of a point

*O*on the line called the origin or endpoint of the ray.### Notation

A ray is named by using the letter that represents its endpoint followed by a second letter that represents another point on the ray.

This is \(\overrightarrow{OD}\):

**Opposite rays**are rays that have the same origin and that extend in opposite directions.

### Properties

- Every point on a line divides the line into two opposite rays.
- Two opposite rays form a straight angle.