# What Is the Point of Intersection of the X-Axis & Y-Axis in a Coordinate System?

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The x and y axes are part of the Cartesian coordinate system, also called the rectangular coordinate system. Coordinates on this system are located by their distance from perpendicular lines (the x and y axes) that intersect. Every line, figure and point in coordinate geometry can be drawn in a coordinate plane using the Cartesian coordinate system.

## Origin of the Cartesian Coordinate System

René Descartes, a French philosopher and mathematician, invented the Cartesian coordinate system. In 1637 he published a book, "Discourse on the Method of Reasoning Well and Seeking Truth in the Sciences," that included a section called "La Géometrie," or Geometry. In this section Descartes described the Cartesian coordinate system, pairing geometry and algebra for the first time.

## How the Coordinate System Works

The Cartesian coordinate system comprises two number lines, one horizontal and one vertical. The horizontal line is known as the x-axis and the vertical line is called the y-axis. These axes intersect to form four quadrants. Because the x and y axes are perpendicular to one another, they intersect only once, in a place called the origin. Coordinates are measured by a set length that equates to distance from the origin.

## How to Describe X and Y Axis Intersection Coordinates

Coordinates are written as (x,y), where x stands for the value on the x (horizontal) axis and y stands for the value on the y (vertical) axis. The place where the x-axis and y-axis meet is at a zero value on both the x and y axes. Because the x and y axes both intersect at zero, the coordinate of their point of intersection is described as (0,0).

## How to Describe Other Coordinates

A point located in quadrant I, on the upper right, has a positive x and y coordinate value, for example (1,1). A point located in quadrant II, on the upper left side, has a negative x and positive y coordinate value, for example (-1,1). A point in quadrant III, on the lower left side, has a negative x and y coordinate value, for example: (-1,-1). A point in quadrant IV, on the lower right side, has a positive x and negative y coordinate value, for example (1,-1).