Rays

What is a Ray?

A ray is a line that has a starting point (O) and extends infinitely in one direction.

Thus, rays have one endpoint, while the other end is open and unbounded.

Points on the ray, excluding the origin, are referred to as interior points of the ray.

The direction in which it extends is indicated by an arrow.

Note: A line can be considered as the union of two rays that originate from the same point but extend in opposite directions. Two rays that lie on the same line are called opposite rays, while the line they share is known as their supporting line. 

There are different ways to denote rays.

In some texts, they are represented by a single lowercase letter, similar to lines. For example, "s".

In other cases, the origin point is denoted by a capital letter followed by the lowercase letter of the ray. For example, "Os".

And so on.