Coordinate Plane Intro

• A Coordinate Plane is a 2-dimensional surface formed by 2 lines. The lines are perpendicular.

• The horizontal line is the x-axis. It tells you how far to move to the left (negative) or right (positive). This number is first.

• The vertical line is the y-axis. It tells you how far to move up (positive) or down (negative). This number is second.

• When plotting a point, go the left or right first. Then go up or down. Think of how you use an elevator.

• The first number is the x-coordinate because it is from the x-axis (horizontal).

• The second number is the y-coordinate because it is from the y-axis (vertical).

Where the x-axis and y-axis intersect is called the origin, this point is always (0,0).

• The horizontal (left-right) number line on the grid is the x-axis.

• The vertical number (up-down) line on the grid is the y-axis.

• Each point on the coordinate grid can be described by an ordered pair of numbers.

• The x-coordinate, the first number in the ordered pair, is the horizontal location, or the distance the point is from 0 in the direction of the x-axis.

• The y-coordinate, the second number in the ordered pair, is the vertical location, or the distance the point is from 0 in the direction of the y-axis.

• The x-axis and the y-axis intersect at the point (0, 0), called the origin.

• Locate the point for which you want to write an ordered pair

• Look below at the x-axis to identify the point’s horizontal distance from 0, which is its x-coordinate.

• Look to the left at the y-axis to identify the point’s vertical distance from 0, which is its y-coordinate.

• So, the ordered pair for the arena is (3, 2)

• Plot the point (5, 7) and label it J.

• From the origin, move right 5 units and then up 7 units.

• Plot and label the point.

Which dot represents 5?

A

B

C

A

B

C

Which dot
represents 1?

x

y

x

y

y = 4
x = 2

x

y

y = 4
x = 6

(6,4)

x

y

x

y

(3,2)

x y

x

y

(­1,0)

x

y

x

y

(­3,­2)

x

y

(0,­1)