## Content description

Introduce the Cartesian coordinate system using all four quadrants (ACMMG143)

Source: Australian Curriculum, Assessment and Reporting Authority (ACARA)

### The Cartesian plane

The Cartesian plane is divided into four quadrants by two perpendicular axes called the x-axis (horizontal) and the y-axis (vertical). These axes intersect at a point called the origin. Sometimes the Cartesian plane is known as the number plane.

The position of any point in the plane can be represented by an ordered pair of numbers (x, y). The first number tells us which line through the x-axis we are on. The second one tells us which line through the y-axis we are on. These ordered pairs are called the coordinates of the point. The coordinates of the point A in the top left quadrant are (−4, 7).