Straight and curved lines
A line can be straight or curved. In geometry, the word line 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.
A line segment is part of a line. Here is an example of a straight line segment:
Lines can get their names from any two points on the line. For example, if a line contains two distinct points, named and , then the line can be called either , or .
Sometimes, lines are also named with just one symbol. In which case, a letter such as might be used.
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: In Euclidean space, two lines are skew if they are not parallel but they never touch.
Line Facts for Kids. Kiddle Encyclopedia.