# What is a coordinate system? Definition and example

A coordinate system refers to two number lines that intersect at right angles. The figure below shows the coordinate system.

Notice how the horizontal line or blue line is called x-axis and the vertical line or red line is called y-axis.

Because the x-axis and the y-axis lie on a plane, we can also call the coordinate system a coordinate plane.

## Why do we need a coordinate system?

The main purpose of a coordinate system is to locate points. Once you know how to locate points, you could also use the coordinate plane to graph lines, quadratic equations, and so forth ...

## Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

- Click on the HTML link code below.
- Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.