10-1 Finding Perimeter

Course 1

HOMEWORK & Learning GoalHOMEWORK & Learning Goal

AIMS PrepAIMS Prep

Lesson PresentationLesson Presentation

Chapter 10 Section 16th Grade Math HOMEWORK

Page 502#6-22 EVENS

Our Learning Goal

Students will be able to find the perimeter and area of polygons; find the area and circumference of circles and find the surface

area and volume of 3D shapes.

Our Learning Goal Assignments• Learn to find the perimeter and missing side lengths of a

polygon.

• Learn to estimate the area of irregular figures and to find the area of rectangles, triangles, and parallelograms.

• Learn to break a polygon into simpler parts to find its area.

• Learn to make a model to explore how area and perimeter are affected by changes in the dimensions of a figure.

• Learn to identify the parts of a circle and to find the circumference and area of a circle.

• Learn to name solid figures.

• Learn to find the surface areas of prisms, pyramids, and cylinders.

• Learn to estimate and find the volumes of rectangular prisms and triangular prisms.

• Learn to find volumes of cylinders.

Today’s Learning Goal Assignment

Learn to find the perimeter and missing side lengths of a polygon.

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10-1 Finding Perimeter

Vocabulary

perimeter

Insert Lesson Title Here

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10-1 Finding Perimeter

The perimeter of a figure is the distance around it. To find the perimeter you can add the lengths of the sides.

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10-1 Finding Perimeter

Additional Example 1: Finding the Perimeter of a Polygon

Find the perimeter of the figure.

2.8 + 3.6 + 3.5 + 3 + 4.3

Add all the side lengths.

The perimeter is 17.2 in.

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10-1 Finding Perimeter

Try This: Example 1

Find the perimeter of the figure.

3.3 + 3.3 + 4.2 + 4.2 + 3

Add all the side lengths.3.3 in. 3.3 in.

4.2 in.4.2 in.

3 in.

The perimeter is 18 in.

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10-1 Finding Perimeter

Additional Example 2: Using a Formula to Find Perimeter

Find the perimeter P of the rectangle.

P = 2l+ 2w

Substitute 12 for l and 3 for w.P = (2 • 12) + (2 • 3)

P = 24 + 6

P = 30

Multiply.

Add.

The perimeter is 30 cm.

12 cm

3 cm

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10-1 Finding Perimeter

Try This: Example 2

Find the perimeter P of the rectangle.

P = 2l + 2w

Substitute 15 for l and 2 for w.P = (2 • 15) + (2 • 2)

P = 30 + 4

P = 34

Multiply.

Add.

The perimeter is 34 cm.

15 cm

2 cm

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10-1 Finding Perimeter

A. What is the length of side a if the perimeter equals 1,471 mm?

P = sum of side lengths

Use the values you know.1,471 = 416 + 272 + 201 + 289 + a

1,471 = 1,178 + a

1,471 – 1,178 = 1,178 + a – 1,178

Add the known lengths.

Subtract 1,178 from both sides.293 = a

Side a is 293 mm long.

Additional Example 3A: Finding Unknown Side Lengths and the Perimeter of a Polygon

Find each unknown measure.

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10-1 Finding Perimeter

Try This: Example 3A

Find each unknown measure.

A. What is the length of side a if the perimeter equals 1,302 mm?

P = sum of side lengths

Use the values you know.1,302 = 212 + 280 + 250 + 240 + a

1,302 = 982 + a

1,302 – 982 = 982 + a – 982

Add the known lengths.

Subtract 982 from both sides.320 = a

Side a is 320 mm long.

212 mm 280 mm

a250 mm

240 mm

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10-1 Finding Perimeter

Additional Example 3B: Finding Unknown Side Lengths and the Perimeter of a Polygon

Find each unknown measure.

B. What is the perimeter of the polygon?

First find the unknown side length.

Find the sides opposite side b.

The length of side b = 50 + 22.

Side b is 72 cm long.

P = 72 + 55 + 50 + 33 + 22 + 22

P = 254

Find the perimeter.

The perimeter of the polygon is 254 cm.

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10-1 Finding Perimeter

72 cm

First find the unknown side length.Find the sides opposite side b.

The length of side b = 12 + 4.

Side b is 16 m long.

P = 14 + 12 + 8 + 4 + 6 + 16

P = 60

Find the perimeter.

The perimeter of the polygon is 60 m.

Try This: Example 3B

Find each unknown measure.

B. What is the perimeter of the polygon?12 m

14 m

b m

8 m

6 m

4 m

16 m

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10-1 Finding Perimeter

l = 4w Find the length.

l = (4 • 19)

l = 76

Substitute 19 for w.

Multiply.

Additional Example 3C: Finding Unknown Side Lengths and the Perimeter of a Polygon

C. The width of a rectangle is 19 cm. What is the perimeter of the rectangle if the length is 4 times the width?

4w

19 cm

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10-1 Finding Perimeter

Additional Example 3C Continued

P = 2l + 2w

Substitute 76 and 19.P = 2(76) + 2 (19)

P = 152 + 38

P = 190

Multiply.

Add.

Use the formula for the perimeter of a rectangle.

The perimeter of the rectangle is 190 cm.

4w

19 cm

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10-1 Finding Perimeter

l = 5w Find the length.

l = (5 • 13)

l = 65

Substitute 13 for w.

Multiply.

Try This: Example 3C

C. The width of a rectangle is 13 cm. What is the perimeter of the rectangle if the length is 5 times the width?

5w

13 cm

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10-1 Finding Perimeter

Try This: Example 3C Continued

65 cm

13 cm

P = 2l + 2w

Substitute 65 and 13.P = 2(65) + 2 (13)

P = 130 + 26

P = 156

Multiply.

Add.

Use the formula for the perimeter of a rectangle.

The perimeter of the rectangle is 156 cm.

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10-1 Finding Perimeter

Don’t forget your proper heading! Trade & Grade!

10-1 Lesson QuizFind each perimeter.

1. 2.

3. What is the perimeter of a polygon with side

lengths of 15 cm, 18 cm, 21 cm, 32 cm, and 26

cm?

4. What is the perimeter of a rectangle with

length 22 cm and width 8 cm?

9 cm

4 ft

Insert Lesson Title Here

112 cm

60 cm

56__

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10-1 Finding Perimeter

6th Grade AIMS PrepWhen you play a game with a friend, there

are lots of tricks, or strategies, that you use to win the game.

Just like the game tricks, there are lots of test-taking tricks to help you “win” when

taking the AIMS Math Test.

What are some test-taking tricks that you use?

AIMS Example 1What is the problem asking us to solve?

Test-Taking Strategy #1Understand the problem!! Read It Thoroughly!