Dilations and Similar Polygons

Choose the correct scale factor:

• 2

• 3

• 1/3

• 1/2

Describe the similarity transformation that maps to (dilations have a center at the origin).

• a dilation with a scale factor of 2 followed by a translation 4 units right and 3 units down.

• a dilation with a scale factor of 1 / 2 followed by a translation 4 units left and 3 units up.

• Translation 4 units right and 3 units down followed by a dilation with a scale factor 2.

• Translation 4 units left and 3 units up followed by a dilation with a scale factor 1 / 2.

The two polygons are similar.

Find the value of x

Find the scale factor

Find the ratio of the perimeter.

Value of x: ____, Scale factor: ____, Ratio of perimeter: ____

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

• an enlargement

• a reduction

• a scale factor

• bigger

A dilation of a figure is ___________.

• Congruent

• Similar

• Neither congruent nor similar

• Not proportional

Tell whether the two figures are congruent or similar.

• Congruent, because their sides are the same.

• Congruent, because their sides are proportional.

• Similar, because their sides are the same.

• Similar, because their sides are proportional.

• They are not congruent or similar.

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

• reduction

• enlargement

• scale

• not proportional

Similar figures have the same ______ but different ______. 

• measure; shapes

• sizes; shapes

• value; measures

• shape; sizes

Which of the following is the algebraic representation for a dilation?

• (x, y) → (x, 3y)

• (x, y) → (3x, 3y)

• (x, y) → (x, y - 3)

• (x, y) → (.5x, .4y)

Are the two polygons similar? If not, explain why. (They are not drawn to scale, but you can assume all angles are 90°.)

• Yes

• No; Not enough information to tell

• No; 5 ⁄ 25 ≠ 6 ⁄ 10

• No; 5 ⁄ 25 ≠ 8 ⁄ 41