Square OABC is drawn on a centimetre grid. O is (0,0) A is (2,0) B is (2,2) C is (0,2) Write down how many invariant points there are on the perimeter of the square when OABC is rotated 90 degrees clockwise, centre (2,0).

Answer:
One invariant point;
Point A = (2, 0)
Step-by-step explanation:
The coordinates of the square vertices are;
O = (0, 0)
A = (2, 0)
B = (2, 2)
C = (0, 2)
Therefore, we have by 90° clockwise rotation;
O' = (2, 2)
A' = (2, 0)
B' = (4, 0)
C' = (2, 4)
Therefore, since only A' (2, 0) = A (2, 0), we have only one invariant point on the perimeter of the square when it is rotated 90° about the center (2, 0) which is the point A = (2, 0).