Split 90 into two parts so tha one part is 4 times the other part

so, we'll end up with two parts, one being 4 times larger than the other, namely if the other is 1 slice, then the large part is 4 slices, meaning both parts will be on a 4:1 ratio.

well, simply enough, we can simply split 90 in (4+1) pieces, and then distribute accordingly to each part

the answer is (4,3)

since the rule for r0, 90º is (-y,x) and it was already applied to form the image, all you have to do is reverse the answer using this formula.