Line Definition

In Mathematics, a line is a 1D figure that doesn’t have any endpoint. It is formed by joining multiple points extended in opposite directions. All points that are being joined to form a line must be collinear.

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Lines have great importance in one of the most studied and important fields of Mathematics i.e. Geometry. It is used to form multiple geometrical shapes like a triangle, a rectangle, and a square.

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A small part of any line is termed a line segment. It is a particular section of the line that has endpoints. In simple words, we can draw multiple line segments from a single line.

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Types of lines

Depending on the direction, a line has multiple types. Here we have listed some of the most common types of lines.

Horizontal lines

A line that extends in the horizontal direction or is parallel to the x-axis will be called a horizontal line.

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Vertical lines

All those lines that extend from top to bottom or are parallel to the y-axis will be termed vertical lines.

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Perpendicular lines

If two lines meet or intersect each other at an angle of 90 degrees, they will be called perpendicular lines.

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Parallel lines

Two or more lines that keep extending side by side and never touch each other are called parallel lines. These lines never meet and make an angle of 0 degrees with each other.

Note:

• A line has no endpoints.
• A line is formed by joining multiple points extended in opposite directions.
• All geometrical shapes (except circles) are made by joining lines.
• The simplest figure formed by joining lines in Geometry is Triangle (Three Lines).

FAQ's

Are line and line segments the same?

No line segment is a particular section of the whole line. We can say that line is a complete figure while a line segment is a particular part of that figure.

Does a line have thickness?

No, a line has no thickness that’s why it is called a 1D figure.

Does a line have endpoints?

No, a line has no endpoints but it keeps extending in opposite directions.

What is the major difference between a line and a line segment?

A line is a whole figure while a line segment is a particular section of that figure.

Can we draw a line with an endpoint?

Yes, we can draw a line with an endpoint but it will not be termed a line. Such a line will be termed a Ray instead of a line or a line segment.