1. Scale drawing

2. goal I can use ratios and proportions to create scale drawings.
I can compute length and area from scale drawings using strategies such as proportions.

3. Vocabulary
Scale drawings and scale models are used to represent objects that are too large or too small to be drawn or built to actual size.
The scale gives the ratio that compares the measurement of the drawing or model to the measurement of the real object.

4. What are scale drawings? Scale drawings are everywhere!
On Maps
Footprints of houses
Vehicle design
Can you think of any more?

5. Use a map scale FORMULA Solve by using the steps to solve a proportion
Scale Length
𝑚𝑎𝑝 𝑎𝑐𝑡𝑢𝑎𝑙 = =
Solve by using the steps to solve a proportion
-cross multiply
-divide

6. The distance between the two cities is 60 miles.
Map Scales
Ratios and proportions can be used to find distances using a scale.
Example:
1 inch = 15 miles
The distance from Jacksonville to Smithtown on a map is 4 inches. How many miles are between these cities?
1 in.
15 mi.
4 in n =
The distance between the two cities is miles.
1n = 60
n = 60

7. Let’s Try
On a map, the distance from Akron to Cleveland measure 2 centimeters. What is the actual distance if the scale of the map shows that 1 centimeter is equal to 30 kilometers.

8. Let’s Try Scale Actual 𝑚𝑎𝑝 𝑎𝑐𝑡𝑢𝑎𝑙 = 1 30 = 2 𝑥 60 = x
On a map, the distance from Akron to Cleveland measure 2 centimeters. What is the actual distance if the scale of the map shows that 1 centimeter is equal to 30 kilometers.
Scale Actual
𝑚𝑎𝑝 𝑎𝑐𝑡𝑢𝑎𝑙 = = 𝑥
60 = x
The actual distance from Akron to Cleveland is 60 km

9. Let’s try
An engineer makes a model of a bridge using a scale of 1 inch = 3 yards. The length of the actual bridge is 50 yards. What is the length of the model?

10. Let’s try
An engineer makes a model of a bridge using a scale of 1 inch = 3 yards. The length of the actual bridge is 50 yards. What is the length of the model?
scale length
𝑚𝑜𝑑𝑒𝑙 𝑎𝑐𝑡𝑢𝑎𝑙 = 𝑥 50
3x =
3𝑥 =
x =

11. Let’s Try: TB page 581 #15
A model of a tree is made using a scale of 1 inch = 25 feet. What is the height of the actual tree if the height of the model is inches?