Question

Quadrilateral army is rotated 90° about the origin

Answer 1

Sorry I am late but the I think it is this, I don’t know the answer but here is what I know. answer is: Imagine a rectangle that has one vertex at the origin and the opposite vertex is A. Now that you can see the image of A(3,4) under the rotation is A’(-4,3). It is easier to rotate the points that lie on the axes, and these help us find the image of A.
POINT: (3,0) (0,4) (3,4)
IMAGE (3,0) (-4,0) (-4,3)