Coordinate System

The First Quadrant

The first thing you have to know about the coordinate plane are the axes.

• The x-axis is horizontal. In the first quadrant the x-axis starts at 0 and goes to the right.

• The y-axis is vertical. In the first quadrant, the y-axis starts and 0 and goes up.

x-axis

y-axis

0 on the y-axis

0 on the x-axisOrigin

The origin is the point where the x-axis and the y-axis meet.

The coordinate plane is displayed below. It is made up of a horizontal number line (x-axis) and a vertical number line (y-axis).

Points on the coordinate plane are identified by combining their locations on the x-axis and the y-axis. (x,y)

1. This point did not move

along the x-axis. Its value on the x-axis is 0.

2. The point has not traveled up the y-axis. Its y-value is 0.

3. The name of this point is (0,0).

This point is the origin. Always start here when finding coordinates on the grid.

1. Count along the x-axis. This point is 2 units across the x-axis.

2. Count up the y-axis. This point is 1 unit up the y-axis.

3. Name the point. When naming points, give the x-value first and the y-value second. This point is (2,1).

In this example,• The point has not moved

along the x-axis. Its x-value is 0.

• The point moved 3 units up the y-axis. Its y-value is 3.

• The name for this point is (0,3).

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