A line segment is part of a line. Here is an example of a straight line segment:
Straight and curved lines
A line can be straight or curved. The word line usually means a straight line. A straight line is the shortest distance between two points. A straight line is the line traced by a point moving in a direction that does not change.
Lines can get their names from any two points on the line. For example, if a line has a point named "A" on the line and a point named "B" on the line, then the line can be called either "AB" or "BA".
Sometimes, lines are also named with just one letter; for example, line A.
Two lines can be:
- Parallel: Two lines are parallel if they are on the same plane and they never touch.
- Concurrent: Two lines are concurrent if they touch on one point.
- Coincident: Two lines are coincident if they are made of the same points.
- Perpendicular: Two lines are perpendicular if they make four right angles where they touch.
- Skew: Two lines are skew if they are not parallel but they never touch.