Best answer will be marked brainiest w/ !

what are the coordinates of point a of the pre-image?

D₀,₃ (x , y), where:

D stands for dilatation. the sub (0) = center and the sub (3) represents the scale factor. The scale factor "k" being 3, means the actual image has been dilated 3 times versus the pre-image or reciprocally, the pre-image is a reduction of the image by a factor k₁= 1/3

The coordinate of A' in the image A(-3, 6)
The coordinate of A in the pre-image should be A(-3.k₁,  6k₁)

But k₁ =1/3, then A(-3/3 , 6/3) = A(-1 , 2) (Second Answer)

Maybe the answer is 20mm. all i really did was just multiply, which is obvious.