Maps & Scale Drawings

Pg 275-280 in the textbook

Warm up pg 21 IAN

123

2 x

y

27

5

9

5

2515

m

305

3 c

18

6

21

t

4

5213

n

Check homework 1-55 even page 269-272

2. Figures are not similar. The Ratio of the shorter side is 4:2, but the ratio of the longer side is 5:3.

4. 11.2 ft6. 53°8. 111in10. 8112. 614.Height of a flag pole is hard to

measure but you can use indirect measurement.

16. school bus tires are all circles, basketballs are all spheres; baseball diamonds are squares.

18. 3 ft20. 1022. 90°24. 3626. 4428. $58830. B32.B

Check homework 1-55 even page 269-272

34.

X=

36. 2.8 cm38. 5g40. 8.7 oz42.

xwidth

length 12

1

8.1

3

26

5

16

44.

46.

48.

50. -8

52. 17

54. 3

8

31

6

13

4

18

POP Quiz

Maps & Scale Drawings pg 22

• What is a scale drawing?

• A scale drawing is an enlarged or reduced drawing of an object that is similar to the actual object.

• Example-Maps and floor plans

Maps & Scale Drawings pg 22

• What is a scale? • A scale is the ratio that compares a length in a drawing to the actual corresponding length in the actual object.

Example:Is a 30 mile road is 1 in. long on a map, you can write the scale of the mapin these three ways.

1 in : 30 mi 1 in=30 mimiles

in

30

1

Example pg 22 IAN

• You have a scale drawing of a boat. The length of the boat on the drawing is 3 cm. What is the actual length of the boat?

• The scale of the drawing is 1 cm= 1.5 meters1. Write the scale in the form 2. Then write a proportion in which each ratio compares cm to

meters.3. Let n represent the length of the boat.

Drawing (cm)→ ← Drawing (cm)Actual (m) → ← Actual (m)4. Solve for n5. n=4.5m

m

cm

5.1

1

n

3

5.1

1

Check for understanding pg 22 IAN

• If the mast of the boat is 10 cm tall on the drawing, and the scale is 1 cm =1.5 meters, about how tall is the mast of the actual boat?

Answer15 meters

Real world problem solving pg 22

• Turn in the text books to page 276 Geography Find the actual distance from charlotte to Winston-

Salem.Step 1 Use a cm ruler to find the map distance from Charlotte to

Winston Salem. The amp distance is about 1.6 cm.Step 2: Use a proportion to find the actual distance. Let n

Represent the actual distance. Map (cm) → ← Map (cm)Actual length(km) → ← Actual length (km)

N=120

n

5.1

75

1

Check for understanding

• Using the map on page 276 find the acutal distance between

• Charlotte and Raleigh• Raleigh and Winston Salem

Finding the Scale pg 22 IAN

** you can use the GCF to find the scale of a drawing or a model**

Refer to the model boxcar shown at the right. The actual length of a boxcar is 609 in. What is the scale of the model?

Scale length→Actual length→

We divided by the GCF of 7So the scale of the drawingIs 1 in : 87 in.

|←←←←←← 7 in.→→→→|

87

1

609

7

Homework pg 23 IAN

Page 277 1-43 odd

Extra Credit Quiz gradeComplete the investigation on page 280Plan a trip.