Dilating Figures to Create Similar Figures

What is the definition of scale factor?

• The number we multiply all side lengths in the original figure by to get the new figure’s lengths

• A transformation that makes a shape bigger or smaller based on a scale factor

• The point where a line crosses the y-axis

• The starting point from which we measure distances in a dilation

What is the definition of similar figures?

• The number we multiply all side lengths in the original figure by to get the new figure’s lengths

• A transformation that makes a shape bigger or smaller based on a scale factor

• Figures that have the same angle measures and proportional side lengths

• Figures that have the same angle measures and the same side lengths

When dilating by a scale factor less than one, the shape will...

• get bigger

• get smaller

• stay the same size

When dilating by a scale factor of one, the shape will...

• get bigger

• get smaller

• stay the same size

Are these triangles similar?

• Yes

• No

Are the rectangles similar?

• No, the angles are the same, but the side lengths are not proportional.

• Yes, the angles are the same and the side lengths are proportional.

Triangle ABC is translated 3 units up and 2 units left, then it is dilated by a scale factor of 1/2 using (0,0) as the center to create triangle A'B'C'. Are the two triangles similar or congruent?

• Similar, because the dilation changed the original size.

• Similar, because the shape was translated.

• Not similar, because the dilation changed the original size.

• Not similar, because the shape was translated.

Triangle ABC is dilated by a scale factor of 3 about the origin. Angle A is 5 degrees. What is the measure of Angle A' after the dilation?

• 15 degrees

• 8 degrees

• 5 degrees

• 10 degrees

What is the definition of center of dilation?

• Figures that have the same angle measures and the same side lengths

• A transformation that makes a shape bigger or smaller based on a scale factor

• The point where a line crosses the y-axis

• The starting point from which we measure distances in a dilation

• (4, -12)

• (1, -3)

• (1, -6)

• (2, -3)