Help Me! Geometry...?

Question

Question #1
What coordinates represent the image of point (0,-3) under a dilation with center (-2, -4) and a scale factor of 3?

A) (4,-1)
B) (0,-9)
C) (-6,-6)
D) (-6,-12)

Question #2
Point A has coordinates (6,2) Which coordinates represent A, the image of A under a dilation at (2,-2) with a scale factor of 1/2?

A) (3,1)
B) (4,0)
C) (8,6)
D) (12,4)

Question #3
Line segment CD has endpoints C(-2, 3) and D (-2,2). What are the coordinates of C, the image of C under a dilation centered at point D with a scale factor of 2?

A) (-4,6)
B) (-4,4)
C) (-2,4)
D) (-2,1)

Question #4
At the beginning of the summer, Tommy had $350 in the bank. Each week he deposited another $75. Determine if the relationship?

A) direct variation
B) linear but not a direct variation
C) nonlinear

Question #5
Triangle K' (-1,3), L' (1,-1), M' (3,5) is dilation of KLM with scale factor 2 and the center of dilation at (1,1). What are the coordinates of K'L'M'?

A) K'(-3,5), L'(1,-3), M'(5,9)
B) K' (-2,6), L'(2,-2), M'(6,10)
C) K' (0,2), L'(1,0), M'(2,3)
D) K'(1,5), L'(3,1), M'(5,7)

az_lender · Accepted Answer

1.  Delta-y = +1, Delta-x = +2
In a dilation with scale factor 3, the new delta-y should be +3, 
and the new delta-x should be + 6, so the image is
(-2+6, -4+3) = (4,-1).  Answer (A)

#2.  Delta-y = +4, Delta-x = +4
In a dilation with scale factor 1/2, the new delta-y should be +2,
and the new delta-x should be + 2, so the image is
(2+2,-2+2) = (4,0).  Answer (B)

#3.  Delta-y = +1, Delta-x = 0.
In a dilation with scale factor 2, the new delta-y should be +2,
and the new delta-x should be 0, so the image is
(-2+0, 2+2) = (-2,4).  Answer(C)

#4.  (B) linear, but not a direct variation, since it didn't start at 0.

#5.  You just gave the coordinates of K'L'M'.   But I think the error is in the question.
Maybe they wanted the original triangle?  Which would be answer (C).

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Help Me! Geometry...?

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