Properties of the Vertical Lines

A vertical line is a line perpendicular to another surface or line that is considered as the base. Here you get familiarized with the properties of the vertical line, its equation, and the slope of a vertical.

A vertical line is always a straight line that goes up to down or down to up. Vertical lines are also known as standing lines. The lines that join the bases of a square or rectangle are the vertical lines that we usually draw.

A step-by-step guide to properties of the vertical line

A vertical line is a line on the coordinate plane where all the points on the line have the same \(x\)-coordinate. When we draw the points of the function \(x = a\), on a coordinate plane, we find that a vertical line is obtained by joining the coordinates.

In the image below, \(L1\) and \(L2\) are the two vertical lines. All the points in the \(L1\) have only \(a\) as the \(x\)-coordinate for all the values of \(y\), and all the points in the \(L2\) have only \(-a\) as the \(x\)-coordinate for all the values of \(y\).

Vertical line equation

The equation of a vertical line is \(x = a\) or \(x = -a\), where \(x\) is the coordinate of \(x\) at any point on the line and \(a\) is where the line crosses the \(x\)-intercept.

The slope of a vertical line

A vertical line has an undefined slope. According to the definition of slope, we calculate the slope as follows:

\(m=\frac {(y_2-y_1)}{(x_2-x_1)}\)

Now, since the \(x\)-coordinate remains constant on a vertical line, therefore we have \(x_2=x_1=x\). So, the slope of the vertical line is \(m=\frac{(y_2-y_1)}{(x-x)}=\frac{(y_2-y_1)}{0}\), which is not defined as the denominator is zero.

The \(x\) coordinates remain the same for all the points on the vertical line and there is no run horizontally. Thus the slope of a vertical line is undefined.