Mathematics for IGCSE & O level - Transformations (Section 5 - No. 48)
If a figure is rotated 90 degrees counterclockwise about the origin, what happens to the point (x, y)?
(x, y) becomes (-x, y)
(x, y) becomes (-y, x)
(x, y) becomes (y, -x)
(x, y) becomes (y, x)
Paliwanag
A 90-degree counterclockwise rotation about the origin transforms (x, y) to (-y, x).