By definition, a line exists in only one dimension, is perfectly straight and extends forever in both directions. Lines can be described by their relationships with other lines, such as parallel, perpendicular or intersecting.
A line can be formed by connecting any two points and extending beyond them. Without another figure to interact with the line, it has no other intrinsic properties. Some geometric figures that are often associated with lines are line segments and rays. Line segments have two endpoints, and rays have one endpoint and extend forever in only one direction.
Interesting line facts:
- Two lines that exists on the same plane and never intersect are called parallel lines.
- Two lines that intersect at a 90-degree angle are called perpendicular lines.
- A line that splits a side or segment down the middle is called a bisecting line.
- A line that passes through multiple vertices in a polygon creates a diagonal.
- A line that touches one point on a curve but does not pass through it is considered tangent to that curve.
- Lines can be defined by y=mx+b, an equation that relates y-values to an x-value multiplied by the slope and added to a constant y-intercept. An example is the line y = 2x + 1.