To find the coordinates of point \( W' \) after a 90-degree rotation around the origin, we can use the rotation mapping rules. For a 90-degree counterclockwise rotation about the origin, the transformation rule for a point \( (x, y) \) is given by:
\[ (x, y) \rightarrow (-y, x) \]
Given the coordinates of point \( W(-4, 7) \):
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Identify \( x \) and \( y \):
- \( x = -4 \)
- \( y = 7 \)
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Apply the rotation rule:
- \( W' = (-y, x) \)
- This gives us \( W' = (-7, -4) \)
Thus, after a 90-degree counterclockwise rotation about the origin, the coordinates of \( W' \) are \( \boxed{(-7, -4)} \).