Coordinate System

coordinate plane is formed by two number lines in a plane that intersect at right angles.   The two number lines intersect at 0 on each number line and this point of intersection is called the origin.   The two number lines are called axes.   The horizontal axis is called the x-axis.   The vertical axis is called the y-axis.   The coordinate plane is divided into 4 sections called quadrants.

coordinate plane.jpg

An ordered pair is a pair of numbers, (x, y) that indicate the position of a point on the Cartesian Plane. The numbers in an ordered pair are called coordinates.   The first number is called the x-coordinate and the second number is called the y-coordinate.   The x-coordinate tells how far to move right (positive) or left (negative) from the origin.   The y-coordinate tells how far to move up (positive) or down (negative).   The ordered pair for the origin is (0, 0).

To graph the ordered pair (1, 2), begin at the origin, count over 1 unit to the right along the x-axis, and then count up two units along the y-axis and draw the point.

Just remember, x comes before y in the alphabet, so you will always move along the x-axis first.

If you aren’t sure on how to plot points, here’s a video.

Practice

CP1CP2

What are the coordinates of each point?

CP3

 

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