1. Scale Drawings & Models

2. Scale Drawings & Models
Distances on a scale drawing or model are proportional to real-life distances. The scale is determined by the ratio of a length on a drawing or model to its corresponding actual length.

3. Examples
The local school district has made a scale model of a campus of Engels Middle School including a proposed new building. The scale of the model is 1 inch = 3 feet.
New Building
Gym
Parking
Academic Building

4. Example Continued…
An existing gym is 8 inches tall in the model. How tall is the actual gymnasium?
Set up a proportion…
1 8
3 X
New Building
Gym =
Parking
Academic Building
1(x) = 3(8)
X = 24 feet tall

5. To find the scale factor for scale drawings and models, write the ratio given by the scale in simplest form.
Write the ratio of 1 inch to feet in simplest form.
1 inch 1 in.
1 Feet 16 in. 1 3
Conversion:
1 foot = 12 inches = 1 3

6. = Example… 0.5 inch 5 inch 3 miles X miles4
On a map, two cities are 5 inches apart. The scale of the map is 0.5 inch = 3 miles. What is the actual distance between the towns?
Set up a proportion. 3 4
0.5X = 3(5 )
0.5X = 17.25
X = 34.5 miles 3 4
0.5 inch 5 inch
3 miles X miles =

7. Example Set up a proportion. =
Marta is making a scale drawing of her apartment for a school project. The apartment is 28 feet wide. On her drawing, the apartment is 7 inches wide. What is the scale of Marta’s drawing?
Set up a proportion.
28 feet
28 feet 4 feet
7 inches 1 inch =
1 inch = 4 feet