If a dilation has center at the origin and scale factor 2, then what is the preimage point that would map to (4,8)?

Question

anonymous · Answer

How do you solve this?

anonymous · Answer

@jim_thompson5910

jim_thompson5910 · Answer

you have some unknown point (x,y)

jim_thompson5910 · Answer

x maps to 4
y maps to 8

jim_thompson5910 · Answer

k*x = 4
2x = 4 .. the scale factor k is 2
x = ??

anonymous · Answer

X would be 2

anonymous · Answer

So you would just divdie by two.

jim_thompson5910 · Answer

k*y = 8
2*y = 8
y = ??

anonymous · Answer

4

anonymous · Answer

So the answer would be (2,4)

anonymous · Answer

So lets day if you have another question saying that  the scale factor is three and the preimage points are (3,12) Would you divide by 3?

jim_thompson5910 · Answer

jim_thompson5910 · Answer

Notice how the preimage is the original and the image is the new figure (after you do some transformation to it)

jim_thompson5910 · Answer

in the previous problem, we had the image (4,8)

we didn't know the preimage, so we undid multiplication to find it

anonymous · Answer

Oh okay I get it so the first answer would be (2,4)

jim_thompson5910 · Answer

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