Horizontal Line – Definition with Examples

What Is a Horizontal Line?

Imagine you have a paper, and someone asks you to draw a line. What possibilities will cross your mind? Well, there are a few ways you could do this.

If you were bored, you would most probably just end up drawing a random motion like the one shown below—a skew line.

And if you wanted to think like a mathematician or an artist; you would imagine a tree or something standing and draw a line from top to bottom as shown below—a vertical line.

You could also think of a car or something lying down and sketch your line from left to right as shown below—a horizontal line.

A horizontal line is a sleeping line. It is a straight line that goes from left to right or right to left. The word horizontal is derived from the word “horizon”, which is the line where the earth and sky appear to be meeting far far away. 

Horizontal Lines Around Us

We see horizontal lines all around us in shapes, objects, figures, and drawings. 

Here are some examples of horizontal lines. 

Horizontal Lines in Objects:

Horizontal Lines in Math:

Horizontal lines are the building blocks of so many 2D and 3D shapes in elementary geometry. Squares, triangles, rectangles, cubes, trapezoids, prisms are just some basic examples of shapes in which we can observe horizontal lines.

Horizontal Lines in Coordinate Planes

In coordinate geometry, horizontal lines are defined as lines parallel to the x-axis. If two points on a line have the same y-coordinate points then the line is said to be horizontal.

In the given image, AB is a horizontal line parallel to the x-axis and if you observe carefully, the y-coordinate of both points A and B are the same. Another interesting thing to note about the horizontal lines is that they are always perpendicular to the vertical lines.

Drawing a Horizontal Line

Using a Ruler:

To draw a horizontal line using a ruler, keep the ruler in sleeping position, parallel to the edge of the page, and draw a line from left to right or right to left. 

To draw a horizontal line on a coordinate plane

Follow these steps:

• Plot any point on the coordinate plane. For example, (1, 2).
• Identify the y-coordinate of the point marked. Here, it is 2.
• Plot another point on the coordinate plane, such that its y-coordinate is the same as the previous point plotted. For example, (–5, 2).
• Join the two points plotted using a ruler to get a horizontal line. 

Uses of Horizontal Lines

Horizontal lines are used in symmetry and photography. 

A horizontal line of symmetry runs across the image from left to right (or vice versa) and divides the image into identical halves. 

Cameras are designed to take photographs in landscape (horizontal) or portrait (vertical) mode. In horizontal mode, photographs are wider than they are tall. In vertical mode, photographs are taller than they are wide. Our eyes see the surroundings horizontally, giving a wider view rather than a taller one.

Horizontal Line and Vertical Line

Horizontal Line	Vertical Line
It is a sleeping line that goes from left to right or vice versa.	It is a standing line that goes from top to bottom or vice versa.
It is parallel to the x-axis.	It is parallel to the y-axis.
It is perpendicular to the y-axis.	It is perpendicular to the x-axis.

Solved Examples 

Example 1: Which line segments represent horizontal lines?

Solution:

Lines BC and AD are horizontal lines.

Example 2: Identify the lines indicated by the arrows in each of the following shapes.

Solution:

1. Horizontal line
2. Vertical line
3. Horizontal line
4. Vertical line

Example 3: Identify the horizontal lines in the given shape.

Solution:

AB, EF, and CD are the horizontal lines in the given shapes.

Example 4: Name five English alphabets that have horizontal lines.

Solution:

E, F, H, L, T

Practice Problems

Horizontal Line Attend this Quiz & Test your knowledge. 1 Which one of the following is the horizontal line? A B C D CorrectIncorrect Correct answer is: A A horizontal line is a sleeping line. 2 How many horizontal lines does the given figure have? 1 2 3 4 CorrectIncorrect Correct answer is: 3 There are 3 straight lines that go from left to right or right to left 3 At what time the minute hand of a clock will be horizontal? 12 o’clock Quarter past 12 Half past 12 12:40 pm CorrectIncorrect Correct answer is: Quarter past 12 At a quarter past 12 minutes hand will be at 3. So, the minute hand will be horizontal.

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