Proportions Using Scale Drawing

​Scaling with Proportions

Math 7

​

When the scale factor is less than 1​

​Reduction

​

When the scale factor is greater than 1​

Enlargement

Multiple Choice

What is the formula for scale factor?

• $$\frac{new}{original}$$

• $$\frac{original}{new}$$

Multiple Choice

What is the scale factor from the small fry (original) to the large fry (new)?

• 1/3

• 48

• 4

• 3

Multiple Choice

If the scale factor is less than one, the new figure will be

• larger

• smaller

Multiple Choice

If the scale factor is greater than one, the new figure will be

• smaller

• larger

​Solving Questions with Scale

​Use proportions!

Multiple Choice

This scale drawing shows a parking lot. What is the actual (real) length of the longer side of the lot? 

• 63 m
• 235 m
• 315 m
• 630 m

Multiple Choice

On a map, the distance between two towns in 2.6 cm. The scale of the map is

1 cm : 50 km. What is the actual distance between the two towns?

• 100 km

• 130 km

• 70 km

• 150 km

Multiple Choice

On a map, the distance between Albany and Syracuse is 9.5 inches. The map has a scale of 1 inch to 15 miles. What is the actual distance, in miles, between Albany and Syracuse?

• 0.633 miles

• 1.579 miles

• 142.5 miles

• 152.5 miles

Multiple Choice

Robin is building a scale model of a bridge. The model has a scale of 1 inch to 4 feet. The actual length of the bridge is 26 feet. What is the length, in inches, of the model bridge?

• $$6\frac{1}{5}\ inches$$  

• $$6\frac{1}{2}\ inches$$  

• 22 inches

• 104 inches

Multiple Choice

The distance from Point A to Point B on a scale drawing is 6 cm. If the scale is 1cm : 10m. What is the actual distance from A to B?

• 6 m
• 10 m
• 18 m
• 60 m

Multiple Choice

The scale drawing car length is 3 cm. If the scale is 1 cm:4 ft, what is the actual car length?

• 12 feet
• 16 feet 
• 10 feet
• 4 feet

Multiple Choice

Desmond measured a city park and made a scale drawing. The scale he used was 1 centimeter : 9 meters. The actual width of the soccer field is 54 meters. How wide is the field in the drawing?

• 6 cm

• 486 cm

• 9 cm

• 54 cm

​Similar Figures

​Same shape but different size.

All angles are congruent

​

All sides are proportional​

Multiple Choice

What is true about the shape and size of similar figures?

• Same shape and same size
• Same shape and not the same size
• Different shape and same size
• Different shape and not the same size

Multiple Choice

What is true about the sides of similar figures?

• Corresponding sides are proportional.
• Corresponding sides are congruent.
• Opposite sides are proportional.
• Opposite sides are congruent.

Multiple Choice

What is true about the angles of similar figures?

• Corresponding angles are proportional.

• Corresponding angles are congruent.

• Opposite angles are proportional.

• Opposite angles are congruent.

Multiple Choice

The _________tells us how many times larger or smaller a figure is from the original.

• Scale factor

• Angle

• Side lengths

• Units

Multiple Choice

Which proportion would allow you to solve for the missing side, x?

• A

• B

• C

• D

Multiple Choice

The two rectangles are similar figures. What is the measurement of x?

• 21
• 1.25
• 20
• 4

Multiple Choice

The pair of figures is similar. Find the missing side.

• x = 20
• x = 12
• x = 5
• x = 4

Multiple Choice

Given the similar triangles shown, find missing side

• 5
• 7
• 9
• 11

Multiple Choice

Solve for X.

• 2 ft

• 3 ft

• 4 ft

• 6 ft