To rotate a point \((x, y)\) 90 degrees counterclockwise about the origin, you can use the rotation mapping rule:
\[ (x, y) \rightarrow (-y, x) \]
For the point \(W(3, 7)\), we apply the rule:
- Identify the coordinates: \(x = 3\) and \(y = 7\).
- Substitute into the rotation rule:
\[ W' = (-y, x) = (-7, 3) \]
Thus, the coordinates of \(W'\) after a 90-degree counterclockwise rotation about the origin are \((-7, 3)\).