Dilating Figures

A triangle has vertices with coordinates (2,0), (3, -1) and (-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 the vertices of the image?

• (5,3), (6,2), (1,-2)

• (6,0), (9,-3), (-6,-15)

• (2/3,0), (1,-1/3), (-2/3,-5/3)

• (-1,-3), (0,-4), (-5,-8)

What is the rule for the dilation pictured below?

• (x, y) → (½x, ½y)

• (x, y) → (x + 2, y + 2)

• (x, y) → (2x, 2y)

• (x, y) → (2x, 3y)

What is the scale factor from the triangle to the left to the triangle on the right?

• 2

• 3/2

• 2/3

• 1/2

What is the scale factor from ΔDEF to ΔABC?

• 1/2

• 7/3

• 2

• 10/3

What is the scale factor from ABCD to MNOP?

• 2/3

• 3/2

• 2

• 3

One side of a triangle on the coordinate plane is 4 units long. If it undergoes a dilation about the origin with a scale factor of 2, what will the length be?

• 2

• 4

• 8

• 16

Which of the following are Dilations?

• (x, y) → (x, 3y)

• (x, y) → (3x, 3y)

• (x, y) → (x, y - 3)

• (x, y) → (.5x, .4y)

Sides in similar figures must be proportional.  

• True

• False 

Solve for X.

• 2 ft

• 3 ft

• 4 ft

• 6 ft

Tell whether the two figures are similar. Explain your reasoning.

• Yes, similar because they are the same shape and side lengths are proportional.

• No, not similar because they are the same shape, but side lengths are not proportional.

• Yes, same shape

• No, different sizes