Question

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.

Answer 1

if you dilate a point (x,y) about (0,0) with scale factor a, then you have the new point (ax,ay).

So for example.
If I dilate a point (2,-3) about (0,0) with scale factor -2, then I have the new point (-4,6).
I got that new point by multiplying both 2 and -3 by the scale factor -2.

Answer 2

So
what number times 1 is 4?

Answer 3

4

Answer 4

ok so you have figure what your scale factor should be

Answer 5

that is what you multiply your old x and y by
to get your new x and y

Answer 6

so what do you think y should be?

Answer 7

I'm not sure but I'd go with D

Answer 8

@bree16
do you understand all you need to do is
multiply both your old x and y by 4 to get the new point?

(1, 4) → (4, y)
1(4)=4
so
4(4)=y