Scale Drawing and Scale Drawing and ModelsModels

VocabularyVocabulary

• Scale Drawing or a Scale Model: Used to represent an object that is too large or too small to be drawn or built at actual size.

• Scale: The ratio of a length on a drawing or model to its actual length.

Things to knowThings to know• Scale Drawings and Models and the objects

they represent are similar figures

• You can use the scale of a drawing to find the scale factor by writing a ratio showing the scale length to the actual length.

• The two sides of the ratio must use the same unit, so it is usually necessary to convert the bigger unit to the smaller unit.

• Distances on a scale drawing are proportional to distances in real life.

On a drawing using a scale of 1cm=50km.If the distance from Grenada, Mississippi to Little Rock, Arkansas is 5.2 centimeters. What is this distance in kilometers???

Method 1 Write and solve a proportion

Method 2Write and solve an equation

WORDSThe actual distance is 50 kilometers per centimeter of map distance.

VARIABLESLet a represent the actual distance in kilometers.Let m represent the map distance in kilometers

EQUATION A = 50 · m

A passenger car of a model train is 6 inches long. If the actual car is 80 feet long, what is the scale of the model?

Let x represent the actual length of the train. Write and solve a proportion to find the scale of the model.

Find the scale factor for the model train

Find the scale factor for each scale

A) 1 inch = 15 feet

B) 10 cm = 2.5 m

The model Mr. Vicario made of the building he designed was 25.5 centimeters tall. If the actual building is to be 64 centimeters tall, what is the scale of his model?