We know, Scale dilation factor = Final Image / Original Image magnitude
Here, Final Image magn. = -1 - (-4) = -1 +4 = 3
Original Image magn. = -3 - (-12) = -3 + 12 = 9
So, Dilation factor = 3/9 = 1/3
In short, Your Answer would be 1/3
Hope this helps!
