Question

Figure ABCD is a parallelogram with point C (−4, 1). Figure ABCD is rotated 90° clockwise to form figure A′B′C′D′. What coordinate would be the output for point C'?

C' (1, 4)
C' (1, −4)
C' (−1, −4)
C' (−1, 4)

Answer 1

The answer is that coordinate C' is (-1, -4). The formula for rotating something 90° is (x, y) -> (-y, x), so (-4, 1) -> (-1, -4).