1. Bellwork
Draw the following figure on your bellwork paper and then scale it by Draw the post-image.
What is the perimeter of the pre-image? The post-image?
16 inches
12 inches

2. Lesson Scale Drawings

3. Today…
Section 1: What is a scale drawing? Section 2: Using proportions to find unknown quantities involving scale drawings. Section 3: Reproducing a figure using a scale. Section 4: Finding area and perimeter of shapes involving scale.

4. Scale Drawings
Let me explain using real life…

5. Mississippi State university!
Home of the Bulldogs!

6. Mississippi state is famous for…
Cowbells of course!
And Football!

7. Mississippi state is famous for…
#1 Vet School in the Country!
And, having great dairy
products such as
cheese!
MSU is an agricultural
school for those that
didn’t know.

8. Mississippi State University is also famous for their

9. School of Architecture
Architects design buildings and help in the construction of buildings!
As most students are driving around campus late at night with their radios turned up as loud as possible having fun, architect students are working in Giles Hall designing buildings! Not an easy major, but very rewarding to see the finished product!
Giles Hall

10. Scale drawings in their line of work.
Architects use scale drawings everyday
in their line of work.

11. What is a scale drawing? Blueprints Maps Scale Models
A Scale Drawing… is an ENLARGED or REDUCED drawing of an actual object.
Blueprints
We will talk about three kinds of scale drawings. Blueprints, maps, and scale models.
Maps
Scale Models

12. Blueprints
Let’s talk about Blueprints first.

13. Blueprints of a house How would you like to live on the BEACH?
This blueprint has a scale of
2 inches : 4 feet
2 inches is the drawing length.
4 feet is the actual length.
If something measures 2 inches on the blueprint, then in real life the measurement would actually be 4 feet.
2 inches : 4 feet

14. Maps
Now, let’s move on to Maps.

15. Maps
This map is a scale drawing because it is a reduced drawing of the state of Mississippi.
2 inches is the map/drawing length. 25 miles is the actual length.
If you measure 2 inches on the map, it would actually be 25 miles in real life.
Scale 2 inches = 25 miles

16. Scale Models
Last, but not least…Scale Models.

17. Independence Day Scale 1:12 Scale Models
Did anyone see the movie “Independence Day” starring Will Smith? It is one of my favorite movies.
So… do you really think they blew up the actual white house? No way!
A scale model was built, and it was used in the movie to shoot that scene.
Scale :12

18. Moving on…
Section 1: What is a scale drawing? Section 2: Using proportions to find unknown quantities involving scale. Section 3: Reproducing a figure using a scale. Section 4: Finding area and perimeter of shapes involving scale.

19. Today, when setting up your proportions keep this in mind…
You can use proportions to solve problems dealing with scales drawings.
Today, when setting up your proportions
keep this in mind…
Proportion: an equation stating that two ratios (fractions) are equal. For example:
68 𝑣𝑜𝑡𝑒𝑠 𝑓𝑜𝑟 𝑀𝑟. 𝑀𝑒𝑎𝑟𝑠 100 𝑝𝑒𝑜𝑝𝑙𝑒 𝑠𝑢𝑟𝑣𝑒𝑦𝑒𝑑 = 34 𝑣𝑜𝑡𝑒𝑠 𝑓𝑜𝑟 𝑀𝑟. 𝑀𝑒𝑎𝑟𝑠 50 𝑝𝑒𝑜𝑝𝑙𝑒 𝑠𝑢𝑟𝑣𝑒𝑦𝑒𝑑

20. When setting up a proportion, you always want to put the “like things” across from each other.
For example, look at this proportion:
𝟏 𝒊𝒏𝒄𝒉 𝟐 𝒇𝒆𝒆𝒕 = 𝟓 𝒊𝒏𝒄𝒉𝒆𝒔 𝒙 𝒇𝒆𝒆𝒕
Notice…
The 𝒊𝒏𝒄𝒉𝒆𝒔 are across from the 𝒊𝒏𝒄𝒉𝒆𝒔 and
the 𝒇𝒆𝒆𝒕 are across from the 𝒇𝒆𝒆𝒕.

21. Example: The scale of a map is 2 inches = 25 miles.
Find the actual distance if the map distance
is 3 inches.
Step 1:
Take the scale and make that the 1st ratio.
Step 2:
Take the other information provided and make that your 2nd ratio.
Step 3:
Cross Multiply
Step 4:
Solve the equation.
𝟐 𝒊𝒏 𝟐𝟓 𝒎𝒊 = 𝟑 𝒊𝒏 𝒙
𝟐𝒙 = 𝟕𝟓
𝒙=𝟑𝟕.𝟓 𝒎𝒊
After setting up the scale as the first ratio, point out that we just have one more number left to figure out where it needs to go which is the 3 inches.
They should easily be able to figure out that it goes on the top because the “like things” go across from each other. We want the inches to go across
from the inches. Another way of saying it is that we want the drawing length to go across from the drawing length. That means our x goes on the bottom.
You are given the 3 inches. It goes on the top because the “like things” go across from each other.
That means our unknown (𝒙) goes on the bottom.

22. Guided Practice
On an architect’s drawing of a house, 1 inch represents 1.5 feet. If the actual bedroom window is 3 feet, how many inches will it be on the drawing?
Step 1 and 𝑖𝑛𝑐ℎ 1.5 𝑓𝑒𝑒𝑡 = 𝑥 3 𝑓𝑒𝑒𝑡
Step x = 3
Step 𝑥=2 𝑖𝑛𝑐ℎ𝑒𝑠
Scale: 1 in = 1.5 ft

23. You Try!
The scale on a map shows that 5 centimeters = 2 kilometers. Part A: What number of centimeters on the map represents an actual distance of 5 kilometers? Part B: What is the actual number of kilometers that is represented by 2 centimeters on the map?
Part A: 5 𝑐𝑚 2 𝑘𝑚 = 𝑥 5 𝑘𝑚 𝑥 = 12.5 𝑐𝑚
Part B: 5 𝑐𝑚 2 𝑘𝑚 = 2 𝑐𝑚 𝑥 𝑥 =0.8 𝑘𝑚

24. Moving on…
Section 1: What is a scale drawing? Section 2: Using proportions to find unknown quantities involving scale. Section 3: Reproducing a figure using a scale. Section 4: Finding area and perimeter of shapes involving scale.

25. Reproducing a figure using a scale
We’ll move straight to an example problem…

26. Example:. An architect made this drawing to represent a. swimming pool
Example: An architect made this drawing to represent a swimming pool. If the scale is 1 inch = 3 feet, what are the dimensions of the actual swimming pool?
To find the actual dimensions of the pool, set up and solve a proportion using the scale for each side.
𝟏 𝒊𝒏 𝟑 𝒇𝒕 = 𝟓 𝒊𝒏 𝒙
5 in.
𝒙 = 𝟏𝟓 𝒇𝒕
Swimming Pool
4 in.
𝟏 𝒊𝒏 𝟑 𝒇𝒕 = 𝟒 𝒊𝒏 𝒙
𝒙 = 𝟏𝟐 𝒇𝒕
Answer: The dimensions of the actual swimming pool are
12 ft by 15 ft

27. Last section…
Section 1: What is a scale drawing? Section 2: Using proportions to find unknown quantities involving scale. Section 3: Reproducing a figure using a scale. Section 4: Finding area and perimeter of shapes involving scale.

28. Guided Practice
An architect made this drawing to represent a swimming pool.
If the scale is 1 inch = 3 feet, what is the perimeter and area of the actual swimming pool?
Swimming Pool
7 in.
5 in.
Teachers:
Find the actual length of each side by setting up and solving a proportion.
𝟏 𝐢𝐧 𝟑𝐟𝐭 = 𝟕 𝐢𝐧 𝐱 x = 21 ft 𝟏 𝐢𝐧 𝟑𝐟𝐭 = 𝟓 𝐢𝐧 𝐱 x = 15 ft
Perimeter: = 72 ft
Area: b x h = 21 x 15 = 315 ft²

29. You Try
Julie is constructing a scale model of her room. The rectangular room is 10.5 inches by 8 inches.
If 1 inch represents 2 feet of the actual room, what is the perimeter and area of Julie’s room?
Teachers:
Find the actual length of each side by setting up and solving a proportion.
𝟏 𝐢𝐧 𝟐𝐟𝐭 = 𝟏𝟎.𝟓 𝐢𝐧 𝐱 x = 21 ft 𝟏 𝐢𝐧 𝟐𝐟𝐭 = 𝟖 𝐢𝐧 𝐱 x = 16 ft
Perimeter: = 74 ft
Area: b x h = 21 x 16 = 336 ft²

30. Closure
A scale drawing is a reduced (or enlarged) drawing of an actual object.
What is a example of a scale drawing?
How do you solve problems that involve scales?
The first ratio is always your ________?
The second ratio is set up from the _______?
When setting up ANY proportion, what is VERY IMPORTANT to remember?
Blueprints, Maps, Scale Models
Set up a Proportion
Scale
The other # in the problem.
Put “like things” across from each other!

31. Time for Classwork!
Handout classwork.

32. End of PowerPoint
Handout classwork.