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You can use a spreadsheet to see how the perimeter and area of a figure
are affected when one or both dimensions change.
Explore what happens when one or both dimensions of a rectangle are
doubled. Enter the new dimensions described below into the appropriate cells.
Step 1 Double the original length by typing
26 into cell A2, which is twice the original
length of the rectangle.
Step 2 Type 6 into cell B2 to represent the
original width. The program automatically
calculates the new perimeter and area.
The new perimeter is 64, and the new area is 156. The change in the perimeter
is an increase of 26, or twice the original length. The new area is twice the
original area.
Use a spreadsheet to divide one or both dimensions in half.
Explore what happens when one or both dimensions of a rectangle are halved.
Enter the new dimensions described below into the appropriate cells.
First divide the length in half, and use the given width of 6 inches.
- Divide the original length of 13 inches by 2.
Type 6.5, which is half of the original length of
the rectangle, into cell A2. The width remains
the same, 6 inches.
The new perimeter changes to 25 inches, and the
new area changes to 39 square inches. The change
in the perimeter is a decrease of 13, the original
length. The new area is half of the original area.
Now divide the width in half, and use the original length of 13 inches.
- Divide the original width by 2. Type 3, which
is half of the original width of the rectangle,
into cell B2.
The new perimeter is 32, and the new area is 39.
The change in the perimeter is a decrease of 6,
which is the original width. The new area is half
of the original area.
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Lesson 10-12 for exercise sets.
- Make a conjecture, and verify it with a spreadsheet.
What would happen to the perimeter and area if you were to double
the original length and the original width of the rectangle? Use a
spreadsheet to verify your conjecture. Describe the results.
2.Discuss and Write Explain how you would use spreadsheet software to
find the area and perimeter of a square that has sides measuring 4.7 cm.
