In mathematics, straight lines are those lines which never intersect each other and help in the formation of straight angles. The straight lines are classified into three types: horizontal lines, vertical lines, and oblique or slanted lines. A horizontal line can be defined as a line that moves from left to right or right to left with respect to the coordinate ‘x’ in the plane. There are various examples of horizontal lines in real life such as moving railway tracks or lines, the steps of a staircase, and many more. We can also find examples of these lines in the geometrical shapes. For example, the three-dimensional figures, quadrilateral, and many more are made up of horizontal lines. It is also known as sleeping lines as it is in a sleeping posture. In this article, we shall discuss the topics related to straight lines such as: what are vertical lines, properties of vertical lines, comparison between vertical and horizontal lines.

## What Are Vertical Lines?

As mentioned above, there are various types of straight lines. One of them is the vertical lines. It can be defined as a type of line, which is perpendicular to another line or surface which is also known as the base. In the coordinate geometry, you may find that the vertical lines are parallel (not intersecting lines ) to the y axis and are perpendicular to the lines which are horizontal. The property of a horizontal line is exactly opposite to the vertical lines, it is parallel to the X-axis and perpendicular to the vertical lines. These lines always move or go from bottom to top or vice-versa. It is also regarded by a different name, standing lines. In some geometrical faces such as square and rectangle, you may find the lines which are vertical. In the next section, we shall learn about some important properties of a vertical line.

### Some Important Properties of a Vertical Line

Vertical lines are those lines that move from bottom to top or vice versa. As with every other notation in mathematics, vertical lines also possess some important properties. The following are some significant properties of a vertical line:

- A vertical line is always parallel to the y-axis. It never intersects the y-axis. Therefore, you may find that the equation of a line that is vertical does not consist of a y-intercept.
- The mathematical equation given for a vertical line is always written as, x = a or x = -a where x is denoted as the coordinate of the given plane and ‘a’ signifies the line which crosses the x-intercept.
- In a vertical line, the denominator of the slope is always written as zero. This is due to the x- coordinated. They are not defined or undefined.
- The basic application of vertical lines is to check whether either the relation is a function or not in mathematics.

## Horizontal Line Vs Vertical Line

The following points mentioned below discuss some significant distinctive points which differ a horizontal line from a vertical line or vice-versa.

- Ahorizontal linecan be defined as a line that moves from left to right or right to left with respect to the coordinate ‘x’ in the plane. These lines always move or go from bottom to top or vice-versa. Horizontal lines are also known as sleeping lines whereas vertical lines are known as standing lines.
- A vertical line is always parallel to the y-axis. It never intersects the y-axis. A horizontal line is parallel to the x-axis.
- One common feature between both of them is that these lines are perpendicular to one another.

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