How Many Points Do You Need to Define a Line

A line is defined by two points and is written as shown below with an arrowhead. Two lines that meet in a point are called intersecting lines. A plane extends infinitely in two dimensions.

How many points do we need to define a line?

Three points. A line (straight line) can be thought of as a connected set of infinitely many points. It extends infinitely far in two opposite directions.

Can a line have 2 points?

For example, for any two distinct points, there is a unique line containing them, and any two distinct lines intersect in at most one point. In two dimensions (i.e., the Euclidean plane), two lines which do not intersect are called parallel.