What is difference between line and line segment?

The difference between a line and a line segment is fundamental in geometry:

Line: - Extends infinitely in both directions - No endpoints - goes on forever - Represented with arrows at both ends: ↔ - Named by any two points on it with a double-headed arrow above: ↔AB - Has infinite length

Line Segment: - Has two definite endpoints - Finite length - measurable distance between endpoints - Represented as a straight path between two points - Named by its endpoints with a line above: AB - Does not extend beyond its endpoints

Visual comparison: - Line: <---A---B---> (continues forever both ways) - Line Segment: A---B (starts and ends at A and B)

Real-world examples: - Line: A laser beam in space (theoretical), a thought extending infinitely - Line Segment: A pencil, a piece of string, a road between two cities

Mathematical implications: - You can measure the length of a line segment - A line has no measurable length (infinite) - A line segment is part of a line between two points

Understanding this distinction is crucial for geometry, as lines and line segments have different properties and are used differently in mathematical proofs and constructions.