Reflections and Dilations

∆QRS contains the points: Q(4, 2) R(5, 1) S(3,7). If the triangle is reflected across the y-axis, what will S' be?

• S'(3, 7)

• S'(-3, 7)

• S'(-3, -7)

• S'(3, 7)

Reflect over x-axis. Which point would be at (3, -6)

• A

• B

• C

• H

What Transformation is visible?

• Reflection

• Translation

• Rotation

• Dilation

What type of transformation occurred?

• Translation

• Reflection

• Dilation

Answer explanation

a DILATION changes the SIZE of an image, therefore a dilation has occurred.

What scale factor was used to dilate IJKL to create I'J'K'L'?

• SF=3

• SF=4

Answer explanation

The image was reduced, so the SF must be less than 1. Set up the ration NEW over OLD.

The triangle was reflected across the y-axis.  Which algebraic representation best describes this transformation?

What type of transformation occurred?

• Translation

• Reflection

• Dilation

Answer explanation

Notice the letter positions, they have FLIPPED. Therefore, it is a reFlection.

• The image got smaller because the scale factor is greater than one.

• The image got bigger because the scale factor is greater than one.

• The image got smaller because the scale factor is less than one.

• The image is congruent because the scale factor is less than one.

What scale factor was used to dilate DFGH to create D'F'G'H'?

• SF=2

• SF=4

Answer explanation

The image was reduced, so the SF must be less than 1. Set up the ration NEW over OLD.

Which rule describes the dilations from PNDM to P'N'D'M'?

Answer explanation

The image was enlarged, so the SF must be greater than 1. Set up the ratio NEW over OLD.