Determine the coordinates of the vertices of the rotation image of the trapezoid ABCD (in the figure) if it is rotated 90 degrees clockwise about point Y.

Question

Determine the coordinates of the vertices of the rotation image of the trapezoid ABCD (in the figure) if it is rotated 90 degrees clockwise about point Y.

Answer 1

Step 1: Subtract x,y coordinates of Y from x,y coordinates of A, B, C and D.

e.g. Y is (2,5), A is (4,7), so A' is (2,2)

Step 2: Map x,y coordinates of A, B, C and D from Step 1 as follows: (x,y) -> (y,-x)

e.g. A' is (2,2), so A'' is (2,-2)

Step 3: Add x,y coordinates of Y to x,y coordinates of A, B, C and D from Step 2.

e.g. A'' is (2,-2) so A''' is (4,3).