Ch. 8 Review

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

Add all the sides together

C = 2 ⋅ 3.14 ⋅ 6
= 37.68

C = 2⋅π⋅r

C = 3.14 ⋅ 20
= 62.8 cm

C = π⋅d

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

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

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

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

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

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

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

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

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

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

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

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

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

14

14

21

A = 14 + 21

= 35 in²

14

21

24

24

8

A = 24 + 8

= 32 ft²

24

8

21

21

A = 21 + 6 + 21

= 48 ft²

21

6

21

21

6

21

A = 21 + 6 + 21

= 48 ft²

21

6

21

A = b⋅h = 9 ⋅ 12 = 54 cm²
2 2

A = b⋅h = 11 ⋅ 8 = 44 cm²
2 2

A = b⋅h = 23 ⋅ 7 = 80.5 cm²
2 2

7

10

7

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

10

7

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

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

10

7

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