# how do i get coordinates of image in geometry rotations?

draw a counter clockwise rotation of 90 degrees about (0,0) forP(-5,0), Q(-2,-2),R(-3,-4),S(-5,-6)

what are the coordinates of P'Q'R'S'?

also can you expain?????

### 1 Answer

- Anonymous10 years agoFavorite Answer
A rotation by 90° about the origin. The general rule for a rotation by 90° about the origin is (A,B) (-B, A) where A is composed of coordinates making up the object.

lets say you have a point P(2,-3). The 90 degree rotation would place it at P'(3,2) under our general rule. You will see that once you plot these two points if you draw a line from the origin to point P and another line to P' the two lines will be perpendiular thus forming a 90 degree angle. that is a good way to visually check to see if you have actually rotated 90 degrees.

Do this for every point in the object and you will end up with a 90 degree rotation

Thus the final coordinates are

P'(0,-5)

Q'(2,-2)

R'(4,-3)

S'(6,-5)

hope this helps you