Rays are used in mathematics to describe a line that has a single endpoint and extends infinitely in the opposite direction. Rays are used to describe a variety of different objects in mathematics, such as angles, lines, and circles. In order to understand rays, it is important to understand how they are defined. This article will explain which pair of undefined terms is used to define a ray.

## What are Rays?

Rays are a type of line that has one endpoint and extends infinitely in the other direction. Rays can be used to describe a variety of different objects in mathematics, such as angles, lines, and circles. Rays are typically represented by an arrow, with the endpoint of the arrow being the endpoint of the ray.

## How are Rays Defined?

Rays are typically defined using two undefined terms: point and direction. The point is the endpoint of the ray, and the direction is the line that extends infinitely in the opposite direction of the point. Together, these two undefined terms can be used to define a ray.

For example, if a ray has a point at (3, 4) and a direction of -1, the ray can be represented by the equation y = -x + 7. This equation describes a line that has a point at (3, 4) and extends infinitely in the negative direction.

In conclusion, rays are defined using two undefined terms: point and direction. The point is the endpoint of the ray, and the direction is the line that extends infinitely in the opposite direction of the point. Together, these two undefined terms can be used to define a ray. Understanding how rays are defined is important for understanding various objects in mathematics, such as angles, lines, and circles.