Dilations and Scale Factors

If point is at N(-1, 2) and point is at N'(-2, 4), what scale factor was point N multiplied by?

• 2

• 3

• 1/3

• 1/2

What is the definition of dilations in mathematical terms?

• to make larger or smaller

• to make larger

• none of the above

• to make smaller

A dilation produces a similar figure

• True

• False

If the scale factor is less than 1, the new figure will be

• an enlargement

• a reduction

• a scale factor

• bigger

What variable represents scale factor in the algebraic representation (x,y) to (kx,ky)?

• x

• y

• z

• k

A dilation is which of the following: 

• only an enlargement

• only a reduction

• Either an enlargement or a reduction

• Neither an enlargement or a reduction

How do you write the algebraic notation when the scale factor is 1/2?

• (x, y) −> (2x, 2y)

• (x, y) −> (1/2x, 1/2y)

• (x, y) −> (-2x, -2y)

• (x, y) −> (2x, 1/2y)

Find the scale factor of the dilation. Then tell whether the dilation is a reduction or an enlargement.

• 2 / 5; reduction

• 5 / 2; enlargement

• 2 / 3; reduction

• 3 / 2; enlargement

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: ____