Question

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

Answer 1

The answer would be: C' (-1, -4)

Rotation of 90° counterclockwise will apply changes to the coordinate as:
1. x'= -y
2. y'= x

The coordinate of point C before rotation is (-4.1). Then the coordinate after rotation would be:
x'= -y
x'= -1

y'= x
y'= -4
C' (-x' y')= C' (-1, -4)