Extend previous understanding of the coordinate plane to plot rational number ordered pairs in all four quadrants and on both axes. Identify the x- or y-axis as the line of reflection when two ordered pairs have an opposite x-or y-coordinate.

Find distances between ordered pairs, limited to the same x-coordinate or the same y-coordinate, represented on the coordinate plane.

Solve mathematical and real-world problems by plotting points on a coordinate plane, including finding the perimeter or area of a rectangle.

The coordinate plane has four quadrants, or sections.

The x-axis is horizontal.

The y-axis is vertical.

To name a point on a coordinate plane, use an ordered pair that lists the x-coordinate, then the y-coordinate, separated by a comma. This is called an ordered pair.

The origin is the point where the x-axis and the y-axis meet. The ordered pair at the origin is (0,0).

These points have the same x-coordinates (2), but their y-coordinates are opposites (3 and -3). These points are reflections of each other, and the line of reflection is the x-axis.

These points have the same y-coordinates (3), but their y-coordinates are opposites (2 and -2). These points are reflections of each other, and the line of reflection is the y-axis.

We will only be working with points that share an x- or y-coordinate. As a result, we will need to look at the coordinate that is different. In this first example, both points share an x-coordinate (2). The y-coordinate of one point is 3, and the y-coordinate of the other point is 1. The difference of 3 and 1 is 2. To find the difference between two numbers, simply subtract.

In this next example, the points also share an x-coordinate (2), but their y-coordinates are a little trickier to work with (3 and -3). We can find the distance between these points by finding the difference of 3 and -3.

3 - (-3) = 6. The distance between these points is 6.

This table shows a set of ordered pairs. After we plot the ordered pairs, we can see that we create a square.

Finding the area and perimeter of this square is just as easy as finding the area and perimeter of any other square. We can see that the side lengths are all 2, so we can use that information to determine the area and perimeter.

The area is 2 x 2 = 4 square units, and the perimeter is 2 + 2 + 2 + 2 or 4 x 2 = 8 units.