3 Dilations and Scale Factors

Dilations and Scale Factors

Multiple Select

Similar figures have ...

• Congruent Angles

• Congruent Side Lengths

• Proportional Angles

• Proportional Side Lengths

Multiple Choice

Are these similar figures?

• Yes

• No

Similar Figures

Multiple Choice

Are the two figures similar?

• Yes

• No

Make sure to set up ratios with corresponding sides

Fill in the Blank

Find x using the proportional relationships of similar figures.

Set up a Proportion and Solve Like an Equation

To do a Dilation on the Coordinate Plane (when centered at the origin)

Multiply by the scale factor!

Dilate the triangle by 3.

F(2, -2), G(2, 2), H(-1, -2)

Multiply by the scale factor!

Dilate the triangle by 3.

F(2, -2), G(2, 2), H(-1, -2)

F'(6, -6), G'(6, 6), H'(-3, -6)

Same Starting Point, Different Factor

Fill in the Blank

Dilate by a scale factor of 5.

A(2, 3), B(1, 4), C(4, 5)

What are the new x and y values for B' ?

,

Multiple Choice

A figure has a point at (3, 4). When dilated by a factor of 2, the new image point is located where?

• (5, 6)

• (5, 8)

• (6, 8)

• (6, 6)

Multiple Choice

Which of the following statements is true about the scale factor (k) for this dilation?

• $$k>1$$

• $$k=1$$

• $$0<k<1$$

Multiple Choice

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

• $$\frac{1}{2}$$

• $$\frac{1}{4}$$

• 4
• 2

Multiple Choice

If triangle ABC was dilated by a scale factor of 3, with the origin as the center of dilation, what would the coordinates of B' be?

• (12,0)

• (12,12)

• (4,3)

• (0,12)

Multiple Choice

State the coordinates of point A after a dilation, with the center of dilation at (0,0), and a scale factor of 1/2.

• (2,2)

• (8,8)

• (0,12)

• (4,12)

Multiple Choice

The red triangle has been dilated by a scale factor of 1/4, with the center of dilation at (0,0), which triangle is it's new image? 

• green triangle 

• red triangle 

• black triangle

• none of these