**Definition of a Ray**

- A ray is a part of a line that begins at a particular point (called the endpoint) and extends endlessly in one direction. A ray is also called half-line.

**How do we name a Ray?**

- A ray is named based on the direction in which it extends.
- A ray is named with its endpoint in the first place, followed by the direction in which its moving.
- In the example shown below, P is the endpoint and Q is the point towards which the ray extends. So, the ray PQ is represented as:

- Look at another example. This ray will be called QP as it starts at Q and extends towards P. So, the ray QP is represented as:

**Solved Example on Ray**

Which of the following is a ray?

Solution:

Step 1:The definition of a ray states that "A ray is a part of a line that begins at a particular point (called the endpoint) and extends endlessly in one direction."

Step 2:As per the defition of a ray, among the figures given only Figure 2 represents a ray.

**Related Terms for Ray**

- Endpoint
- Part of a Line
- Angle
- Vertex