Question

1.After a dilation with a center of (0, 0), a point was mapped as (1, 4) → (4, y). A student determined y to be 16. Evaluate the student's answer.

A.
The student is correct.
B.
The student incorrectly calculated the scale factor to be 4.
C.
The student incorrectly multiplied by the scale factor instead of adding it.
D.
The student incorrectly added the scale factor instead of multiplying by it.

2.Under a dilation centered at the origin, the image is congruent to the preimage. What is the scale factor?

A.
–1 or 0
C.
only 1
B.
0 or 1
D.
–1 or 1

Answer 1

@BTaylor

Answer 2

bro help me out with those one

Answer 3

What do you think the answers are?

Answer 4

for the first one i go with (B) the student incorrectly calculated the scale factor to be 4.

Answer 5

Actually, the scale factor of 4 is correct. 4/1=4, and 16/4=4. The scale factor, in this type of problem, will be: \[k=\frac{x_2}{x_1}\]

Answer 6

so the student is correct then?

Answer 7

yes. For the second one, for what values of k will |x2|=|x1|

Answer 8

x=0,-1,1

Answer 9

so it would be (B) 0 to 1

Answer 10

0 is correct for that formula, but not for the real answer. It is D -1 or 1 because any point, for example (10,6) would stay at (10,6), making the image the same as the preimage. A scale factor of zero means that there is no image.

Answer 11

D ok