A coordinate plane is a two-dimensional plane with an x-axis (horizontal) and a y-axis (vertical). These axes intersect to form a perpendicular line that separates the coordinate plane into four quadrants.
How to Use a Coordinate Plane
You use coordinate planes for plotting points on graphs. Each quadrant is written in Roman numerals and has a different location within the plane. For example, the first quadrant (Quadrant I) lies to the right of the vertical axis and above the horizontal axis: