# Cartesian Plane

The Cartesian plane consists of two directed lines that perpendicularly intersect their respective zero points.

From the figure below, you can understand that

• The horizontal directed line is called the x-axis and the vertical directed line is called the y-axis.
• The point of intersection of the x-axis and the y-axis is called the origin and is denoted by the letter O.

## The Coordinates

• The position of any point on the Cartesian plane is described by using two numbers: (x, y).
• The first number, x, is the horizontal position of the point from the origin. It is called the x-coordinate.
• The second number, y, is the vertical position of the point from the origin. It is called the y-coordinate
• Since a specific order is used to represent the coordinates, they are called ordered pairs.

Let us consider the following example:

The ordered pair (5, 8) represents a point 5 units to the right of the origin in the direction of the x-axis and 8 units above the origin in the direction of the y-axis as shown in the diagram below.

The x-coordinate of point P is 5; and the y-coordinate of point P is 8.

(i.e.) The coordinates of point P are (5, 8).

• For the point P(5, 8), the ordered pair is (5, 8).

So: 5 is the x-coordinate, and 8 is the y-coordinate.

• P(5, 8) means P is 5 units to the right of and 8 units above the origin.

## Example Question:

State the coordinates of each of the points shown on the Cartesian plane: