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Key
Idea
You can use
the formula for the area of a rectangle
to find a formula for the area of a parallelogram. |
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Vocabulary
• base
• height |
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Materials
• grid
paper
• ruler
• scissors |
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How can you use rectangles to find
the areas of parallelograms? |
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| a. |
Copy this parallelogram on grid paper. It has a
base of 6 units and a
height of 3 units. |
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| b. |
Cut
out the parallelogram and draw a dotted
line to form a right triangle. |
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Cut out the triangle and move it to the opposite
side of the parallelogram. |
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| d. |
What
shape did you create? What are its base
and height? What is its area? Use counting
to find the area of your original parallelogram. |
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How can you use a formula to find the
area of a parallelogram? |
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To find the area of a parallelogram, adapt the formula
for the area of a rectangle—just substitute base and height
for length and width. |
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A
= base x height |
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A
= b
x h |
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A
= 7 ft x 4 ft = 28 ft2 |
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Talk
About It |
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| 1. |
Connections
In the Example, which parts
of the parallelogram and the rectangle
are congruent? |
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