To perform a \(-90\)-degree clockwise rotation about the origin, you can use the following rotation mapping formula for a given point \((x, y)\):
\[ (x, y) \rightarrow (y, -x) \]
Let's denote the original coordinates of point \(C\) as \((x, y)\). After applying the rotation formula, the new coordinates \(C'\) will be:
\[ C' = (y, -x) \]
If you provide the coordinates of point \(C\), I can calculate the exact coordinates for \(C'\).