Line Segment – Definition, Formula, Examples

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What is Line Segment?

A line segment is a line section that can link two points

Let us understand the line segment with the help of the diagrams below:

This is a line! It has no endpoints and extends endlessly in both directions.

A Line segment

If you mark two points A and B on it and pick this segment separately, it becomes a line segment.

A and B point on line segment

This line segment has two endpoints A and B whose length is fixed. The length of this line segment is the distance between its endpoints A and B.

So, a line segment is a piece or part of a line having two endpoints. Unlike a line, a line segment has a definite length. 

The length of a line segment can be measured either in metric units such as millimeters, centimeters, or customary units like feet or inches

Symbol of Line

A line segment is usually represented by the bar symbol () on top of the endpoints. Say, a line segment has endpoints P and Q, it can be denoted by $\overline{PQ}$.

Real Life Examples of Line Segment

  • Edges of table.
  • Side of a square or triangle
  • Matchstick.
  • Pencil
  • Edge of a ruler.

How to Measure a Line Segment?

When you have two line segments, you can tell whether a line segment is longer or shorter than the other just by looking at them. We can see that the line segment CD is longer than AB. However, we cannot always rely on observation to find the length of a line segment.

Measure a Line Segment

Follow the given steps to measure the length of a line segment:

Step 1: Pick up a scale to measure the length of a line segment. Generally, smaller line segments are measured using a centimeter scale.

Measure the length of a line segment

Step 2: Identify the line segment you want to measure.

Identify the line segment

Step 3: Place the zero marking of the ruler at the starting point of the line segment.

Placing zero on line segment

Step 4: Read the number on the scale where the line segment ends. In this case, it is 5. So, the length of the given line segment is 5 cm.   

Drawing a Line Segment Using Ruler and Compass

Suppose we need to draw a line segment of length 5 cm. We will follow the given steps:

  • Step 1: Draw a line of any length. Mark a point A on the line, which is the starting point of the line segment.
  • Step 2: Using a ruler, place the pointer of the compass 5 cm apart from the pencil’s lead.
Drawing a Line Segment Using Ruler and Compass
  • Step 3: Place the pointer of the compass at A and mark an arc on the line with the pencil point.
  • Step 4: Mark the point where the arc and the line intersect as B.
  • Step 5: AB is the required line segment of length 5 cm.
Measuring length between A and B point on line segment.

Fun Facts About Line Segments

Two words, line and segment, combine to form a line segment. The word line originates from Latin Segmentum, which means strip, a piece cut off, or a segment of earth, while segment comes from Latin Segmentum, which means strip, a piece cut off, or a segment of earth.

Solved Examples on Line Segments

Example 1: Write the name of given line segments.

Solved Examples of line segments

Solution:

$\overline{PQ}$ , $\overline{XY}$

Example 2: Write all possible line segments in the given figure.

Find all possible line segment

Solution:

$\overline{UV}$, $\overline{VW}$ , $\overline{UW}$

Example 3: Count the number of line segments in the given figure.

Count the number of line segments

Solution:

The given figure is made of 7 line segments.

Practice Problems on Line Segments

Line Segment

Attend this Quiz & Test your knowledge.

1

Determine which of the following has two endpoints:

A ray
A line segment
A line
CorrectIncorrect
Correct answer is: A line segment
A line segment has 2 endpoints.
2

Which of these represent a line segment?

$\overrightarrow{LM}$
$\overleftrightarrow{LM}$
$\overleftarrow{LM}$
$\overline{LM}$
CorrectIncorrect
Correct answer is: $\overline{LM}$
A line segment is usually represented by the bar symbol (—) on top of the endpoints.
3

A rectangle has ______ sides.

2
3
4
5
CorrectIncorrect
Correct answer is: 4
4 line segments make the boundary of a rectangle. Thus, a rectangle has four sides.
4

Which of these is the unit of line segment.

Liters
Millimeter
Kilogram
cubic meter
CorrectIncorrect
Correct answer is: Millimeter
Millimeter is a metric unit to measure the line segment.

Conclusion

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Frequently Asked Questions on Line Segments

 A line segment has endpoints, whereas a line can be extended on both ends indefinitely.

Yes. A ray and a line segment are different. A ray has one endpoint, while a line segment has two. One end of the ray extends indefinitely, whereas, in a line segment, the endpoints are always defined and fixed.

The midpoint of a line segment is the point in the middle of the line segment that divides it into two equal sections. 

 If two figures are the same size and shape, they are congruent. As a result, any two line segments with the same length can be deemed congruent.