Scale Factor for Similar Figures

What is the scale factor from ΔDEF to ΔABC?

• 1/2

• 7/3

• 2

• 10/3

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

• x = 10

• x = 4

• x = 2

• x = 5

Find the missing side length.

• 32

• 35

• 20

• 16

The triangles are similar, solve for the question mark.

• 8

• 12.5

• 18

• 24

Shannon is making three different sizes of blankets from the same material. The first measures 2.5 feet by 2 feet. She wants to enlarge it by a scale factor of 2 to make the second blanket. Then she will enlarge the second one by a scale factor of 1.5 to make the third blanket. What are the dimensions of the third blanket?

• 2.5 feet by 2 feet

• 7.5 feet by 6 feet

• 7.5 by 6

• 5 feet by 4 feet

What does similar mean?

• When two figures have the same Rate of change

• Same size

• Same shape

• When two shapes have the same Scale FactorΔ

Are the following similar? Why or why not?

• Yes

• No, the corresponding angles are not equal.

• No, the ratios of the corresponding sides are not equal.

Are these figures similar? Why or why not?

• Yes, their shapes are the same

• No, their corresponding sides are not equal.

• No, their corresponding sides are not proportional.

• Yes, their corresponding sides are proportional

Two objects that are the same shape but not the same size are _______.

• Congruent

• Vertical

• Similar

• Complementary 

Sides in similar figures must be proportional.  

• True

• False