Lines and Angles
86. The Geometry Basics · Point, Line, Ray, and Segment defined
The four basic geometric objects are clearly distinguished by their endpoints and extension.
A point shows an exact position and has no length, breadth, or thickness. A line segment has two endpoints and a fixed length. A ray has one endpoint and extends endlessly in one direction. A line has no endpoints and extends endlessly in both directions.
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For subscribers · Selina ICSE: Lines and Angles
What this lesson covers
Try to break it
A Point is just a spot with no size. A Line Segment has two fixed ends. A Ray has one fixed end and stretches forever in one direction. A Line stretches forever in both directions.
How you build it
Draw a point, segment, ray, and line.
- Place point A on the canvas.
- Place point B a little away from point A.
- Draw a line segment connecting points A and B.
- Extend one end to form a ray.
- Extend both ends to form a line.
The proof, step by step
Prove that point, line, ray, and segment differ by their endpoints and extension.
- A point is a mark of position. It has no length, breadth, or thickness.
- A line extends infinitely in both directions and has no endpoints.
- A ray starts from a fixed point and extends infinitely in one direction.
- A line segment has two fixed endpoints and a definite length.
Worked example
Which of the following geometric figures has exactly one endpoint and extends infinitely in only one direction?
A ray starts at a fixed point and moves in one direction forever. A line has no endpoints, a segment has two, and a point has none.
- Line Segment
- Ray — correct
- Line
- Point