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Algebra 1

7.1.3 Plotting Measurements

Algebra 17.1.3 Plotting Measurements

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Activity

1.

Use the graphing tool or technology outside the course. Plot some values for the length and area of the garden with perimeter 50 meters on the coordinate plane.

Use your table, or here is a sample table of values if you need one:

Length (meters) Area (square meters)
5 100
10 150
12 156
12.5 156.25
18 126
20 100
24 24
Values for a Rectangular Garden with a Perimeter of 50 Meters
2.

What do you notice about how the plotted points increase and decrease?

3.

The points (3,66)(3,66) and (22,66)(22,66) each represent the length and area of the garden. Plot these two points on a coordinate plane, if you haven’t already done so. What do these points mean in this situation?

4.

Could the point (1,25)(1,25) represent the length and area of the garden?

Video: The Meaning of Points on a Graph

Watch the following video to learn more about the meaning of points on a graph.

Are you ready for more?

Extending Your Thinking

1.

What happens to the area when you interchange the length and width? For example, compare the areas of a rectangle of length 11 meters and width 14 meters with a rectangle of length 14 meters and width 11 meters.

2.

What patterns would you notice if you were to plot more length and area pairs on the graph?

Self Check

The graph below shows a rectangle’s side length and its area. What is true about the point ( 3 , 21 ) ?

  1. The area of the rectangle is 3 square meters.
  2. It is not possible to find the width of the rectangle when the length is 3 meters.
  3. The length of the rectangle is 3 meters, and the area is 21 square meters.
  4. The width of the rectangle is 3 meters, and the area is 21 square meters.

Additional Resources

Determining the Meaning of a Point on a Graph

The graph below shows the relationship between a rectangle’s side length and area.

A scatter plot with length of a rectangle given in inches on the x-axis and area of the rectangle in square inches on the y-axis. There are several data points with varying values; axes range up to 12 and 34, respectively.

What does the point (7,28)(7,28) mean in the situation?

The xx-axis represents the length of the rectangle in inches. So, when x=7x=7, the rectangle has a side length of 7 inches.

The yy-axis represents the area of the rectangle. So, when y=28y=28, the rectangle has an area of 28 square inches.

This also means the rectangle has a width of 4 inches since 7×4=287×4=28.

Try it

Try It: Determining the Meaning of a Point on a Graph

Using the same graph above, determine the meaning of the point (3,24)(3,24) and the width of the rectangle.

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