Line (Geometry)
See It in Action
Two examples of the idea done right—and one common look-alike that is not right.
EXAMPLE
EXAMPLE
NON-EXAMPLE
Definition
In Geometry, a line is one of the most basic and undefined terms, but it has a commonly accepted description.
A line in geometry is a straight, one-dimensional figure that extends infinitely in both directions and has no thickness or endpoints.
Key Characteristics:
It is made up of infinitely many points.
It has no beginning or end.
It is straight and extends forever in both directions.
It is usually labeled with two points on the line (e.g., line AB) or with a lowercase letter (e.g., line l).
Example:
If you have two points A and B, the line passing through them is written as line AB, and it includes all points between A and B, as well as beyond them in both directions.
In diagrams, a line is often represented with arrows on both ends to show it continues infinitely.