Scale Factor and Dilation on Area and Perimeter

If a shape is dilated by a scale factor of 1/2, what is the resulting perimeter?

• The new perimeter is 1/2 the original

• The new perimeter is 2 times the original

• The new perimeter is 1/4 the original

• The new perimeter is 4 times the original

What is the formula that compares the areas of the image and preimage?

• A' = A x sf

• A = A' x sf

• A' = A x sf²

• A = bh

Suppose the dimensions of a pentagon with an area of 12 in² are tripled. What would the area of the new pentagon be?

• 108 in²

• 36 in²

• 72 in²

• 144 in²

Choose the correct scale factor:

• 2

• 3

• 1/3

• 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

Figure ABCD has an area of 4 units². It is then dilated using a scale factor of 4. What is the perimeter of the new figure?

• 32

• 64

• 8

What is the scale factor from triangle ABC to triangle DEF?

• 1/2

• 7/3

• 2/1

• 10/3

Dilate the figure by a scale factor of 3 with the origin as the center of dilation. What are the coordinates of the image?

• A'(9,9) B'(18,18) C'(27,9)

• A'(6,6) B'(9,9) C'(12,6)

• A'(9,9) B'(3,3) C'(6,0)

• A'(1,1) B'(2,2) C'(3,1)

A scale factor of less than one means

• that the image will be larger than the pre-image.

• That the image will be the same as the pre-image.

• That you need to subtract that amount off  of each side.

• That the image will be a reduction of the pre-image.

In a dilation what mathematical operation is used with the scale factor?

• addition 

• subtraction 

• multiplication 

• division