Proportions and Dilations

Solving for Missing Pieces

Find side length X.

• x=25

• x=15

• x=100

• x=30

Dilations-Perform Dilations

State the coordinate of the image of the given point B (4,9) under a dilation with center at the origin with the given scale factor of 2.

• B' (2 , 4.5)

• B' (-8 ,-18)

• B' (8 ,18)

• B' (9 ,4)

Do the ratios form a proportion?

• Yes, they form a proportion.

• No, they do not form a proportion.

Choose the correct scale factor:

• 2

• 3

• 1/3

• 1/2

Triangle ABC has vertices A (-2, 2), B (2, 4) and C (3, -1).  What are the coordinates of A' after a dilation by a scale factor of 2.5?

• (-5, 5)

• (5, -5)

• (5, 10)

• (7.5, -2.5)

Which of the statements is true about the graphed triangles?

• They are similar, because one can be obtained by dilating the other about the origin with a scale factor of 2.

• They are similar, because one can be obtained by dilating the other about the origin with a scale factor of 1/2.

• They are not similar, because one can be obtained by dilating the other about the origin with a scale factor of 2.

• They are not similar, because one can be obtained by dilating the other about the origin with a scale factor of 1/2.

The two figures in each question are similar. Which of the following is true? ΔJMT ∼ ________

• ΔABC

• ΔACB

• ΔBCA

• ΔBAC

• ΔCAB

Which is NOT equivalent to 3:5?

• 15:25

• 9:15

• 21:28

• 30:50

A scale drawing of a billboard uses the scale 4 cm:9 ft. The length of the billboard in the drawing is 11 cm. How long is the actual billboard?

• 13 ft

• 20.75 ft

• 24.75 ft

• 22 ft

A class has 30 students. 18 are boys. What is the ratio of boys to girls?

• 12:18

• 3:2

• 30:18

• 18:7