4.6 MAPS AND SCALE DRAWINGS

I can use proportions to solve problems involving scale.

Scale

Ratio that compares the length in a drawing or model to the corresponding length of the actual object.

A scale drawing is an enlarged or reduced drawing of an object that is proportional to the size of the actual object

Using a Scale Drawing

The length of the side of a house is 3 cm in a scale drawing. If the scale is , what is the actual length of the side of the house?

Notice same units in the top and same units in the bottom

Cross multiply: 1n = 2.5(3) Simplify: n = 7.5 The side of the house is 7.5 m

Finding the Scale of a Model

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

Write a ratio

Write in simplest form

Writing

You want to make a scale model of a sailboat that is 51 ft long and 48 ft tall. You plan to make the model 17 in long. Explain how you would find the height of the model and give the answer.

Maps

The scale of a map is called the key.

So every in on the map represents actual miles.

Find the distance represented by 1 in.

Assignment

ALL P.160 # 7-15, 23