# Horizontal Line – Definition and Equation

## Definition of Horizontal Line

The Horizontal line refers to a line which runs left-to-right across. In the field of geometry, this line is one that runs across the page from left to right across. It is derived from the word ‘horizon’, the sense behind it is that horizontal lines happen to be parallel to the horizon.

In coordinate geometry, a horizontal line is a line in which two points on it have the same Y- coordinate points. The horizontal line is mapped from left to right and it happens to be parallel to the X-axis in the plane coordinate system. Furthermore, it is a straight line that does not make any intercept on the X-axis.

### Equation of Horizontal Line

Horizontal lines consist of a slope of zero. Therefore, when we talk about the slope-intercept equation, y = mx + b, m = 0. The equation for horizontal lines becomes y = b, where b represents the y-coordinate belonging to the y-intercept.

### Examples of Horizontal Line

A wall can serve as a good example of a horizontal line. One must look at a wall and look at where that wall meets the floor. This particular intersection is a horizontal line.

Another example of this line can be the line that separates the sky from the land across a clear plan.Â  The line that separates the sky from the water at the beach is also a notable example.

### Understanding the Horizontal Line

Imagine that in a building you are on the second floor. Moreover, its representation can take place by y=2, which means that if you take 5 steps to the left without going up or down the stairs, you will remain on the second floor. The vertical position that you had has not changed and the line does not rise or fall when one notices it from left to right.

Now, consider yourself in the basement. Its representation takes place by y=-1, which means that if you take 4 steps to the right, you will remain in the basement. Once again the line does not rise or fall from left to right.

In these scenarios, a line drawn through your two positions would be a horizontal line. It doesn’t matter where one decides to start. You could be walking across the eleventh floor of a high building.

It also doesn’t matter how much one moves from left to right or from right to left. In case the ending position happens to be at the same height as the beginning position, a line may be drawn through the two points. This line will be horizontal.

There is another way to think about this line. In this way, one can think of this line as a line that has the same height from any point on the line.

This line is one that has zero slopes. The slope can be defined as the rise/run or (change in y value)/(change in x value).

### Solved Question For You

Question 1: What will be the equation for the horizontal line that passes through (6,2)?

Answer: For the horizontal line, y is constant–that is, y shall always take the same value. Here, y occupies a value of 2 at the point (6, 2). Therefore, the equation for y = 2.

Question 2: What is meant by a horizontal line?

Answer: A horizontal line is simply a line that runs from the left-to-right across. In maths, a horizontal line, when represented on a page, will go from left to right across. The two points on this line tend to have the same Y- coordinate points.

Share with friends

## Customize your course in 30 seconds

##### Which class are you in?
5th
6th
7th
8th
9th
10th
11th
12th
Get ready for all-new Live Classes!
Now learn Live with India's best teachers. Join courses with the best schedule and enjoy fun and interactive classes.
Ashhar Firdausi
IIT Roorkee
Biology
Dr. Nazma Shaik
VTU
Chemistry
Gaurav Tiwari
APJAKTU
Physics
Get Started

Watch lectures, practise questions and take tests on the go.

No thanks.