If the point (x, y) is rotated around the origin 90 degrees then its image is (-y, x)
We consider that 90 degrees mean +90 which means rotating anticlockwise
Since point A is (-2, 1)
Change the sign of y-coordinate and switch the 2 coordinates
A' = (-1, -2)
Answer D
(x, y) rotating by 180 degrees, then its image is (-x, -y) just opposite the signs of the coordinates
(x, y) rotating 270 degrees, then its image is (y, -x), change the sign of x-coordinate and switch the 2 coordinates
All of these rules for rotating anticlockwise (+ve angles)
This is a symmetry for rotation
•If the point (x, y) rotated about the origin by angle 90° counterclockwise, then its image is (-y, x)
•If the point (x, y) rotated about the origin by angle 180° counterclockwise, then its image is (-x, -y)
•If the point (x, y) rotated about the origin by angle 270° counterclockwise, then its image is (y, -x)
•If the point (x, y) rotated about the origin by angle 90° clockwise, then its image is (y, -x)
•If the point (x, y) rotated about the origin by angle 180° clockwise, then its image is (-x, -y)
•If the point (x, y) rotated about the origin by angle 270° clockwise, then its image is (-y, x)
•There is no difference between rotating 180° clockwise or counterclockwise around the origin