Given:
The vertices of the quadrilateral WXYZ are W(2,4), X(4,2), Y(2,1) and Z(0,2)
The graph is rotated 90° about the origin.
We need to determine the coordinates of the quadrilateral W'X'Y'Z'
Coordinates of the quadrilateral W'X'Y'Z':
The rule to transform the coordinates 90° counter clockwise about the origin is given by

Let us substitute the coordinates.
The coordinates of W' is given by

The coordinates of X' is given by

The coordinates of Y' is given by

The coordinates of Z' is given by

Therefore, the coordinates of the vertices W', X', Y' and Z' are (-4,2), (-2,4), (-1,2) and (-2,0) respectively.