1. 5.7 Scale Drawings and Models
Standard: MG 1.3
Objective: Students use scales, ratios, and proportions to solve scale drawing and model problems.

2. Key Concepts
Scale drawing: a 2D drawing of an object reduced to a proportion of the original object.
Scale model: a 3D model of an object reduced to a proportion of the original object.
Scale: the ratio of the dimensions of the large object to the reduced model.

3. Key Concept
Maps, globes, Google maps, blueprints, and model cars are all examples of scale drawings and/or models.
It makes it easier to
understand large objects.

4. Example 1: Find measurement
Since the distance must be proportional to the scale, write and solve a proportion to find the missing value.
Make sure units match when setting up the proportion.

5. Practice 1 The scale on a map reads 1 cm : 200 m. Find the
actual distance if the distance measured on the
map is 7 cm. 5

6. Find the actual distance from LA to Houston.mi
Scale
1 in : 300 mi 6

7. Example 2: Find scale
Just like in example 1, use a proportion to find the missing value.

8. Practice 2
A blueprint shows a house that is 15 cm long and the actual house is 75 m. The scale is 1 cm : ? m. What is the scale?

9. Example 3: Find dimensions
First change the scale to equal units (inches)
Then write and solve the proportion

10. The scale of the house blueprint below is to be 1 in = 8 ft.
If the actual dimensions are 80 ft. by 30 ft., find the map
dimensions x and y. y
Scale
1 in : 8 ft x
Length
Width 10

11. Review What is a scale model or drawing? What is a scale?
How do you solve scale problems?
Give an example of when a scale is used.