Dilations and Similarity in the Coordinate Plane

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.

Triangle REP has the coordinates

R(1, 5), E(–4, –4) and P(6, –4). If the image, R'E'P', has the coordinate

R'(3, 15), find E' and P'.

• E'(-12, -12) P'(18, -12)

• E'(12, 12) P'(-18, 12)

• E'(0.3, 2.7) P' (2, -1.3)

When the scale factor of a dilation is between 0 and 1, the dilation is a reduction (shrinks).

• True

• False

Point B (-10,-6) is dilated with a scale factor of 1/2 and the center of dilation at the origin. What are the coordinated of B'?

• (5,3)

• (20,12)

• (-20,-12)

• (-5,-3)

Figure DMPN is dilated to form figure D'M'P'N. What is the scale factor?

• 2

• 3

• 1/3

• 1/2

Triangle ABC is dilated using a scale factor of 1/2. The center of dilation is at the origin. What are the new coordinates of point A'?

• (-3, 3)

• (-12, 12)

• (-2, 2)

Finish the following similarity statement: Figure DEFGHI ∼ Figure ​ (a)  

• DEFGHI

• D'E'F'G'H'I'

• ABCDEF

• A'B'C'D'E'F'

Figures A, B, C, and D are drawn. The center of dilation is point E. Which of the following figures are similar to figure A? Choose all correct answers.

• Figure B

• Figure C

• Figure D

Triangle EFG is drawn on the coordinate plane. The triangle is dilated by a scale factor of 1/3, with the center of dilation at the origin, to form triangle E'F'G'. Then, triangle E'F'G' is translated 3 units to the right to form triangle E''F''G''. What is the coordinate of E'' ?

Two figures can be similar if they have the _______ shape but _______ size.

• Different, Same

• Same, Same

• Same, Different

• Different, Different