# What is a Vertical Line in Geometry?

In geometry, a line is said to be vertical if it is perpendicular (or at a right angle) to another line. This means that the two lines are intersecting at a single point, and the slopes of the two lines are opposite (one is rising as the other is falling).

For example, if you draw a line on a piece of paper, and then draw another line that is perpendicular to the first line, the second line will be vertical to the first line. The two lines will intersect at a right angle, and the slopes of the two lines will be opposite.

In three-dimensional space, a vertical line is one that passes through the z-axis (the axis that runs up and down). This means that any point on the vertical line has a zero x and y coordinate, but a non-zero z coordinate.

I hope this helps! Let me know if you have any other questions.