Lines, line segments and half lines
Key notes:
Points and Lines
- Point: A point is a specific location in space. It has no dimensions (length, width, or height).
- Line: A line is an infinite collection of points that extends in both directions without end. It has one dimension (length).
Line Segments
- Line Segment: A line segment is a part of a line that is bounded by two points. It has a definite length.
- Endpoints: The two points that define a line segment are called its endpoints.
Half-Lines
- Half-Line: A half-line is a part of a line that starts at a specific point and extends infinitely in one direction. It has one endpoint.
Properties and Relationships
- Collinear Points: Points that lie on the same line are said to be collinear.
- Intersecting Lines: Lines that share a common point are said to intersect.
- Parallel Lines: Lines that do not intersect, even if extended infinitely, are said to be parallel.
- Perpendicular Lines: Lines that intersect at a right angle (90 degrees) are said to be perpendicular.
Learn with an example
📢 What is this?
- line
- line segment
- ray
Now look at this figure:
This is a ray. It has 1 endpoint.
📢 What is this?
- line
- line segment
- ray
Now look at this figure:
This is a line. It never ends.
📢 What is this?
- line
- line segment
- ray
Now look at this figure:
This is a line segment. It has 2 endpoints.
Let’s practice!🖊️
