Lines, Line Segments and Rays

Definition: 

A line is a straight path on a plane that extends forever in both directions with no endpoints.

A line segment is part of a line that has two endpoints and is finite in length

A ray is a line segment that extends indefinitely in one direction

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Example: Use the figure to name each of the following:

a) A line        b) A line segment      c) A ray

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Solution: 

Using the definitions of line, line segment and ray, we can identify these elements in the figure.

Step 1: We know a line extends forever in both directions with no endpoints. Based on the figure, we can identify either Line EC or Line BG to be representative of a line.

Step 2: We know a line segment is part of a line that has two endpoints. Based on the figure, we can name segment DF, segment BG, or segment CE to be representative of a line segment.

Step 3: We know a ray is a line segment that extends indefinitely in one direction. Based on the figure, we can name ray BG, ray CE, ray GB, or ray EC to be representative of a ray.

Note: see the given example for the correct notations when naming lines, line segments and rays.

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