Creating New Scale Drawings Using Ratios and Proportions

This lesson teaches how to create new scale drawings from existing ones using ratios and proportions. It explains the concept of proportions, how to solve them through cross multiplication, and common mistakes to avoid. The lesson also covers using scale drawings to determine actual measurements and how to adjust blueprints for different room sizes. By understanding these concepts, students can accurately create and modify scale drawings.

What is a proportion?

• An equation that relates two equal ratios

• A method to divide numbers

• A way to add fractions

• A technique to multiply numbers

How can you solve a proportion?

• By subtracting the means

• By adding the ratios

• By dividing the extremes

• By cross multiplying

What must you know to use a scale drawing effectively?

• The type of paper

• The artist's name

• The scale being used

• The color of the drawing

If 1 inch represents 3 feet, how long is a 4-inch side in actual feet?

• 10 feet

• 8 feet

• 12 feet

• 15 feet

What is the scale factor if a 4-inch side represents 12 feet and you want it to represent 30 feet?

• 1 to 3

• 3 to 1

• 5 to 2

• 2 to 5

How long should the new short side be if the original was 6 inches and the scale factor is 5/4?

• 9 inches

• 8 inches

• 7.5 inches

• 6 inches

What is the new long side measurement on a blueprint if the original was 8 inches and the scale factor is 5/4?

• 11 inches

• 10 inches

• 9 inches

• 8 inches