A straight line extending from a point.
In math, a ray is a part of a line that starts at one point and goes on forever in one direction. It has a clear beginning but no end!
Rays are straight, just like lines and line segments, but they are unique because they only extend in one direction.
We name a ray using two points: the starting point and another point it passes through. For example, ray AB starts at point A and goes through point B, continuing forever.
Rays are important when we:
- Study angles (an angle is formed by two rays with a common starting point)
- Explore directions and movement in space
- Work with geometry and drawing figures
When Do Students Learn About Rays?
Students begin learning about rays as part of their early geometry lessons.
Grades 2–3 – Introduction to Rays
Students learn the difference between lines, line segments, and rays by identifying and drawing each.
Grades 4–5 – Rays in Angle Measurement
Students use rays to form and measure angles and explore basic geometric constructions.
