The Coordinate SystemLocating PointsPlotting Points

Intro to Algebra

Coordinate Plane

Coordinate Plane

• Y-Axis – The vertical line in the coordinate plane

• X-Axis – The horizontal line in the coordinate plane

• Coordinates – The x-values and the y-values• Origin – The point where the x-axis and the y-

axis meet.

Naming Points

You can use two numbers to name every point in the plane. These two numbers are called an ordered pair.

(x,y)

– Think alphabetically! We always write the x value first and then the y value

Plotting Points

• Think of the coordinate points as directions of how to get to the point from the origin.

• X-Value tells you how far to go left or right– Positive = Right– Negative = Left

• Y-Value tells you how far to go up or down– Positive = Up– Negative = Down

Naming Points

What if they are on an axis?

• Points on the x-axis– The y-value for points on the x-axis is 0

• Points on the y-axis– The x-value for points on the y-axis is 0

Naming Points

Plot Points

1. A (3,2)

2. B (1/2, -2)

3. C (0, 3)

4. D (-2, 0)