What is a ray?

A ray is a part of a line that has one endpoint and extends infinitely in one direction. Think of it like a laser beam or a beam of light shining from a flashlight.

Here are some important aspects of rays:

• Endpoint: A ray always starts at a specific point called its Endpoint.
• Direction: A ray extends indefinitely in a single Direction.
• Notation: Rays are often denoted using two points. The first point is the endpoint, and the second point is any other point on the ray. A small arrow is drawn above the two letters, pointing to the right. For example, ray AB (written as $\overrightarrow{AB}$) starts at point A and passes through point B.
• Comparison to Lines and Line Segments: Unlike a Line, which extends infinitely in both directions, a ray has a definite starting point. Unlike a Line%20Segment, which has two endpoints, a ray has only one.
• Applications: Rays are used in geometry to define angles and are fundamental in understanding concepts like light and vision. They are also useful in various mathematical proofs and constructions.