Dilations and Similarity in the Coordinate Plane

What is Dilation?

• Dilation means to enlarge or reduce a shape

• Dilation means to flip over a line

• Dilation means two figures that look alike

• Dilation means to make a shape smaller

A scale factor that is less than one means

• The pre-image will be enlarged.

• The scale factor should be subtracted from the coordinates.

• The image is larger than the pre-image.

• The pre-image will be reduced.

A triangle has vertices with coordinates A(2,0), B(3, -1) and C(-2,-5). If the triangle is dilated by a scale factor of 3 with the origin as the center of dilation, what are the coordinates of C'?

• (1,-2)

• (-6,-15)

• (-2/3,-5/3)

• (-5,-8)

Are these two figures congruent, similar or neither?

• Congruent

• Neither

• Similar

Is A'B'C' a dilation of ABC?

• Yes

• No

State the coordinate of the image of point B (-10,-6) after a dilation with a scale factor of 1/2.

• (5,3)

• (20,12)

• (-20,-12)

• (-5,-3)

Choose the correct scale factor:

• 2.5

• 1.5

• 3.5

• 4

Are the triangles similar?

• Yes

• No

Are the triangles similar?

• Yes
• No

If two figures are similar, the corresponding angles are...

• Congruent

• Supplementary

• Proportional

• Different