M8 Lesson 87 Scale Drawings

Scale Drawings

Math 8 Lesson 87

Introduction

• What do you notice about the images of Mario?

• What do you wonder about these two versions of Mario?

Scale drawing

In order for an original drawing to be reduced or enlarged, every corresponding side must be PROPORTIONAL to the original measurements.

We use MULTIPLICATION to make things bigger or smaller.

Multiple Select

Which pairs of corresponding sides are proportional?

• The bottom of each shape because 4 times 3 is 12

• The right side of each shape because 4 times 3 is 12

• The left side of each shape because 4 times 3 is 12

• The slanted line on the left because 2.2 times 3 is 6.6.

• The slanted line on the right because 2.2 times 3 is 6.6

Multiple Choice

How is Figure F reduced to Figure B?

• Multiply each side by 1/2

• Multiply each side by 1/3

• Multiply each side by 1/4

• Multiply each side by 1/5

Fill in the Blank

The scale factor is ______ to enlarge triangle ABC to triangle DEF?

Multiple Choice

Which copies are scale drawings when compared to the original triangle?

• 1, 2, and 3

• 1 and 2

• 2 and 3

• 1

• 2

Open Ended

Explain why Copy 3 is NOT a scale drawing of the original triangle.

Open Ended

Is Figure B an enlargement of Figure A? Explain why or why not.

Garden Plot

I made a scale drawing of a garden plot I want to build.

The scale I used was 1 inch = 2 feet.

If the drawing of the garden is 8 inches long by 3 inches wide, what are the dimensions of my garden?

Garden Plot

I can create a proportion to find the length of my garden plot.

Garden Plot

I can create another proportion to find the width of my garden plot.

Fill in the Blank

Use the scale drawing to find the height of the house in feet.

Floor Plans

I want to create a scale drawing of my house so that it fits on a standard piece of paper (8.5" by 11").

What scale factor should I use?

Open Ended

What scale factor should I use for my drawing so it fits on a standard piece of paper?

Multiple Choice

A map is drawn with a scale factor of 1 inch = 10 miles. Two towns on the map are 3 inches apart. In miles, how far apart are the two towns?

• 20 miles

• 30 miles

• 40 miles

• 5 miles

Multiple Choice

A map is drawn with a scale factor of 1 inch = 10 miles. Two towns are 80 miles apart. In inches, how far apart are the two towns on the map?

• 80 inches

• 8 inches

• 5 inches

• 10 inches