Scale Factor in Similar Figures

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

• x = 10

• x = 4

• x = 2

• x = 5

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

• reduction

• enlargement

• scale

• not proportional

What is the scale factor from ΔDEF to ΔABC?

• 1/2

• 7/3

• 2

• 10/3

The triangles are similar, solve for the question mark.

• 8

• 12.5

• 18

• 24

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 

A tree is 12 feet tall and casts a shadow 9 feet long. A building nearby casts a shadow that measures 24 feet. How tall is the building? (Draw a picture, set up a proportion)

• 24 feet

• 21 feet

• 27 feet

• 32 feet

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

• an enlargement

• a reduction

• a scale factor

• bigger