To rotate a point \( (x, y) \) 90 degrees clockwise around the origin, you can use the following transformation:
\[ (x, y) \rightarrow (y, -x) \]
So, for the point \( A(2, 4) \):
- \( x = 2 \)
- \( y = 4 \)
Using the transformation:
\[ (2, 4) \rightarrow (4, -2) \]
Therefore, after a 90-degree clockwise rotation, the new coordinates of point \( A \) would be \( (4, -2) \).