Dilations Review

A dilation means to _________ a figure.

• Flip

• Turn

• Reduce or enlarge a figure

• Slide

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(3,3) B(6,6) C(9,3)

• A'(9,9) B'(18,18) C'(27,9)
• A'(6,6) B'(9,9) C'(12,6)
• A'(0,0) B'(3,3) C'(6,0)
• A'(1,1) B'(2,2) C'(3,1)

The point (8, 12) was dilated to become point (2, 3). What was the scale factor?

• ½
• ¼
• 4
• 2

Dilate Point B by a scale factor of 1/2

• (1.5,-4)
• (-1.5,1)
• (-1,-1.5)
• (-2,-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

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.

A dilation produces a congruent figure

• True

• False

When a dilation has a scale factor greater than one, the dilation is an enlargement.

• True
• False

State the coordinate of the image of the given point B (-10,-6) under a dilation with center at the origin with the given scale factor k = 1/2.

• (5,3)
• (20,12)
• (-20,-12)
• (-5,-3)

The coordinates of triangle ABC are A (-1, 9), B (3, 6) and C (0, 1). Triangle GEF is a dilation of triangle ABC with a scale factor of 1/3. What are the coordinates of triangle GEF?

• A(- 1/3 , -1) B(1, 6) C(1/3 , 0)

• A(-3, 3) B(9, 2) C(0, 1/3 )

• A(- 1/3 , 3) B(1, 2) C(0, 1/3)

• A( 1/3 , 3) B(1, 3) C(0,1/3 )