Similar Shapes and Scale Factor

Tell whether the two figures are similar. Explain your reasoning.

• Yes, similar because they are the same shape and side lengths are proportional.

• No, not similar because they are the same shape, but side lengths are not proportional.

• Yes, same shape

• No, different sizes

Triangle ABC and XYZ are similar.  Use your knowledge of scale factor to find the length of X.

• 20

• 25

• 100

• 40

What is the scale factor of these similar shapes?

• 10

• 7

• 9

• 11

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

• x = 9

• x = 28

• x = 7

• x = 63

The following shapes are similar, the smaller one is the original shape, what is the scale factor?

• 8:12

• 3:2

• 4:8

• 6:12

What is the Scale Factor from Shape A (original) to shape B (new)?

• 1

• 2

• 3

• 4

What is the scale factor from the triangle to the left to the triangle on the right?

• 2

• 3/2

• 2/3

• 1/2

The __________ is the ratio of a length of the new figure to the corresponding length on the original figure.

• reduction

• enlargement

• scale factor

• center of dilation

What is the scale factor of the surface area of these cones?

• 3:5

• 9:25

• 27:125

• 15:60

What is the scale factor from the small shape to the big shape?

• 1/2

• 7/3

• 2

• 10/3