Area of Parallelogram Lesson

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Warm UpOBJECTIVE: SWBAT use an efficient method to find the area of any parallelogram, and explain why it makes sense.

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3) Which of the following shapes are parallelograms? Explain how you know.

A. B. C. D.

1) What is the area of this shape?

2) What is the area of this rectangle?

A = 6 sq unitsA = 24 sq units

Shape A, B and D are all parallelograms!

Launch A

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What is the definition of a parallelogram?

A parallelogram is a quadrilateral that has 2 pairs of parallel sides. Opposite sides have the same length and opposite angles have equal measurements.

Vocabulary

Launch B

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Can you quickly find the area of this parallelogram by counting the unit squares?

Area = 12 square units

1 2 3 4 56 7 8 9 10

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(Wait time: 30 seconds)

Launch B

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Can you quickly find the area of this parallelogram by counting the unit squares?

Launch B

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Your challenge:Develop a more efficient method to determine the area of the parallelogram.

“I don’t have all day. Counting takes way too long!”

Launch C

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Did you have to count squares to find the area of the rectangle?

NO!

Multiplying length x width is a more efficient method for finding the area of a rectangle than counting squares.

A = 6 sq unitsA = 24 sq units

What does it mean to find an efficient method?

Remember the warm up problems?

Launch C

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Let’s consider the first shape in the Warm Up.

How could decomposing (cutting) and composing (putting back together) into another shape help you find the area of this shape?

Explore

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Part 1 - (10 Min)

Work with your PARTNER to find an efficient method of finding the area of a parallelogram.

You will get a parallelogram and a pair of scissors. You can:

-Write on the shape-Draw on it-Use scissors on it

1-Partners2-Share Out

3-Worksheet

In 10 minutes you will be asked to stop and think about it!

HINT

Click on the timer!

Explore – Student Share Out

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Part 2 - (3 Min)

Students share out work.

Explore – Complete top half of worksheet Part 3 - (5 Min) – May work together. Then check on next few slides

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Fill out the top half of your worksheet.

Summary – Sharing Questions #1-5

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#1) Explain what you did to find a quicker way to find the area of the parallelogram.

Summary – Sharing Questions #1-5

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#2) Draw the shapes you decomposed (cut apart) your parallelogram into. Do you know the names of these shapes?

#3) Did you create any new shape or shapes by composing (putting back together in a different way)?

Summary – Sharing Questions #1-5

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#4) What dimensions does your new shape (rectangle) have?

original parallelogram

12 cm

8 cm

The base is

The base is 12 cm. The height is 8 cm.#5) Can you identify those dimensions on the original parallelogram?

also 8 cm.also 12 cm. ...? The height is ...?

rectangle

12 cm

8 cm

Assessment – Exit Ticket!

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Complete and hand in the Exit Ticket before you leave!