When the coordinate is being transformed by rotation - rotated 90° about the origin, the transformed coordinate will be:

The coordinate of the point x and y will switch places and y will be multiplied by -1.
For the given coordinate (-4,0), when rotated 90° about the origin, the coordinate of the transformed point will be:



Therefore, the new coordinate of the point when rotated 90° about the origin will be (0,-4).