Ch. 8 Review

Perimeter

P = 15 + 13 + 9 + 9
= 46 ft

Add all the sides together

Fill in the Blanks

Perimeter of a rectangle

P = 17 + 17 + 27 + 27
= 34 + 54
= 88 m

Add all the sides together

Fill in the Blanks

Fill in the Blanks

Circumference

C = 2 ⋅ 3.14 ⋅ 6
= 37.68

C = 2⋅π⋅r

Fill in the Blanks

Circumference

C = 3.14 ⋅ 20
= 62.8 cm

C = π⋅d

Fill in the Blanks

Finding Radius

C = 2⋅π⋅r
43.96 = 2 ⋅ 3.14 ⋅ r
43.96 = 6.28 ⋅ r




r = 7 ft

The circumference of a circular painting is 43.96 ft. What is the radius of the painting?

6.28

6.28

Finding Diameter

C = π⋅d
59.66 = 3.14 ⋅ r
59.66 = 3.14 ⋅ r




d = 19 ft

The circumference of a circular painting is 59.66 ft. What is the radius of the painting?

3.14

3.14

Finding the Area of a Circle

A = π⋅r²
= 3.14 ⋅ (4)²
= 3.14 ⋅ 16
= 50.24 cm²

Fill in the Blanks

Finding the Area of a Circle

A = π⋅r²
= 3.14 ⋅ (6)²
= 3.14 ⋅ 36
= 113.04 yd²

Fill in the Blanks

Area of a Composite Shape

Area of rectangle
A = 23 ⋅ 14 = 322

Area of semicircle
A = π ⋅ r² = 3.14 ⋅ (7)² = 76.93
2 2

​Total area = 322 + 76.93 = 398.93 ft²

Fill in the Blanks

Area of a Composite Shape

Area of rectangle
A = 93 ⋅ 66 = 6138

Area of 2 semicircles (1 circle)
A = π ⋅ r² = 3.14 ⋅ (33)² = 3419.46

​Total area = 6138 + 3419.46 = 9557.46 m²

Fill in the Blanks

Area of a Composite Shape

Area of rectangle
A = 26 ⋅ 16 = 416

Area of semicircle
A = π ⋅ r² = 3.14 ⋅ (8)² = 100.48
2 2

​Total area = 416 - 100.48 = 315.52 in²

Fill in the Blanks

Area of a Composite Shape

Area of rectangle
A = 37 ⋅ 16 = 592

Area of 2 semicircles (1 circle)
A = π ⋅ r² = 3.14 ⋅ (8)² = 200.96

​Total area = 592 - 200.96 = 391.04 cm²

Fill in the Blanks

Perimeter vs. Area

The distance around a shape

Ex: Nicole walking around the field.

The amount of space inside a shape

Ex: A field being covered by artificial turf

Multiple Choice

The court will have a wood floor.
Which measure would be used in finding the amount of wood needed?

• Perimeter

• Area

Multiple Choice

A strip of tape will be placed around the court.
Which measure would be used in finding the amount of tape needed?

• Perimeter

• Area

Multiple Choice

A silver wire will be placed around the window.
Which measure would be used in finding the amount of wire needed?

• Perimeter

• Area

Multiple Choice

The window's glass will be replaced.
Which measure would be used in finding the amount of glass needed?

• Perimeter

• Area

Word Problem

Rachel is staining the wooden floor of a court. The court is in the shape of a rectangle. It's length is 54 ft and it's width is 30 ft. Supposed each can of wood stain covers 135 sq ft. How many cans will she need to cover the court?

​

30

54

1620

1620 ÷ 135 = 12

12 cans

Word Problem

Chang wants to replace the wooden floor at his gym. The floor is in the shape of a rectangle. Its length is 35 feet and its width is 20 feet. Suppose wood flooring costs $13 for each sq ft. How much will the wood flooring cost for the floor?

​

20

35

700

700 ⋅ 13 = 9100

$9100

Word Problem

Tony wants to paint the ceiling of his restaurant. The ceiling is in the shape of a square. Its side lengths are 44 feet. Suppose each can of paint will cover 242 sq ft. How many cans will he need to paint the ceiling?

​

44

44

1936

1936 ÷ 242 = 7.99

8 cans

Word Problem

Deon wants to replace a glass window in his restaurant. The window is in the shape of a square. Its side lengths are 8 feet. Suppose glass costs $6 for each sq ft. How much will the glass cost to replace the window?

​

8

8

64

64 ⋅ 6 = 384

$384

Area of a composite shape

Area of a composite shape

Area of a composite shape

​2 ft

Area of a composite shape

​2 ft

14

Area of a composite shape

​2 ft

14

21

Area of a composite shape

A = 14 + 21

= 35 in²

​2 ft

14

21

Fill in the Blanks

Area of a composite shape

Area of a composite shape

Area of a composite shape

​8 ft

Area of a composite shape

​8 ft

24

Area of a composite shape

​8 ft

24

8

Area of a composite shape

A = 24 + 8

= 32 ft²

​8 ft

24

8

Fill in the Blanks

Area of a composite shape

Area of a composite shape

Area of a composite shape

21

21

Area of a composite shape

A = 21 + 6 + 21

= 48 ft²

​2 ft

21

6

​2 ft

21

Area of a composite shape

​2 ft

21

6

​2 ft

21

Area of a composite shape

A = 21 + 6 + 21

= 48 ft²

​2 ft

21

6

​2 ft

21

Fill in the Blanks

Area of a Triangle

A = b⋅h = 9 ⋅ 12 = 54 cm²
2 2

Fill in the Blanks

Area of a Triangle

A = b⋅h = 11 ⋅ 8 = 44 cm²
2 2

Fill in the Blanks

Area of a Triangle

A = b⋅h = 23 ⋅ 7 = 80.5 cm²
2 2

Fill in the Blanks

Area of a Ring

7

Area of a Ring

10

7

Area of a Ring

Outer Ring
A = π⋅r² = 3.14 ⋅ (10)² = 314

10

7

Area of a Ring

Outer Ring
A = π⋅r² = 3.14 ⋅ (10)² = 314

Inner Ring
A = π⋅r² = 3.14 ⋅ (7)² = 153.86

10

7

Area of a Ring

Outer Ring
A = π⋅r² = 3.14 ⋅ (10)² = 314

Inner Ring
A = π⋅r² = 3.14 ⋅ (7)² = 153.86

Total: A = 314 - 153.86 = 160.14

10

7

Fill in the Blanks

Fill in the Blanks