# What is a Ray in Geometry

By the end of this lesson, you will be able to

- define ray in geometry.
- interpret how ray is produced from a line.
- demonstrate examples of ray.
- distinguish between ray and line.
- relate line, line segment and ray.

## Ray

A ray is a part of a line that starts at an endpoint and extends infinitely far in one direction. Ray is a part of a line. A ray is well-known as half line.

## How Ray is Produced From Line

Let's explain how a ray is generated in basic geometry.

Given a line and; A and B are two distinct points on the line. Thus, the line is AB.

Let P be a another point between A and B on the line AB.

Split the line into two parts at the point P.

As a result, it produces two parts namely PA and PB.

Each part is called a ray.

Each ray starts from P and it is the end point. Thus P is called the initial point. Both ray consists the point P.

PA is the opposite ray with respect to ray PB.

Thus the ray definition geometry stands as follows.

A ray is the trace of a moving point in straight infinitely far from a fixed point.