# Understanding Lines in Geometry

In geometry, a line is a set of points that extend infinitely in two directions. It has no thickness or width, but it can be thought of as a continuous stretch of points that extend infinitely in both directions.

A line can be described using two points, called the endpoints of the line, and all the points on the line are equidistant from these endpoints. Lines can also be described using their slope, which is the ratio of the vertical change to the horizontal change between two points on the line.

Lines are an important concept in geometry and are used to define shapes, such as triangles and circles, and to describe geometric transformations, such as rotations and reflections. They are also used in many real-world applications, such as architecture, engineering, and computer graphics.