IES ”MARÍA BELLIDO”

What is the Cartesian Plane?

The Cartesian Plane (or coordinate plane) is made up of two directed real lines that

perpendicularly intersection at their respective zero points.

The horizontal axis is called the x-axis. The real numbers on the x-axis increase as

you move to the right.  With respect to the vertical axis, the positive numbers are to

the right of the vertical axis and the negative numbers are to the left of the vertical

axis.

The vertical axis is called the y-axis. The real numbers on the y-axis increase as you

move upward.  With respect to the horizontal axis, the positive number to above the

horizontal axis and the negative numbers are below the horizontal axis.

What is the origin?

 The point where the horizontal axis and the vertical axis intersect is called the

origin.

All points on the plane can be located by indicating where the point is horizontally

(x-coordinate) and where the point is vertically (y-coordinate). 

This location is written in a shorthand of an ordered pair where

The first part of the ordered pair is the horizontal position of the point

and

the second part of the ordered pair is where the vertical position of

the point.

What are quadrants?

The two axes break the Cartesian (o coordinate) Plane into four parts.  These parts

are called quadrants.  The quadrants are numbered I, II, III, and IV started with the

top right quadrant and working counter clockwise.

The points in quadrant I have x-coordinates and y-coordinates which are

both positive. 

The points in quadrant II have x-coordinates which are negative and y-

coordinates which are positive.

The points in quadrant III have x-coordinates and y-coordinates which

are both negative.

The points in quadrant IV have x-coordinates which are positive and y-

coordinates which are negative.

It is assumed that you already know how to graph points in the plane.  This is

intended to be a quick review of the Cartesian Plane .  There are several sources on-

line with additional information about the Cartesian Plane.