Question

Polygon ABCD is drawn with vertices at A(1, 5), B(1, 0), C(−1, −1), D(−4, 2). Determine the image vertices of A′ if the preimage is rotated 270° counterclockwise.

A′(−1, −5)
A′(−1, 5)
A′(−5, 1)
A′(5, −1

Answer 1

(d) A'(5, -1)

Explanation:

You want the coordinates of A(1, 5) after it has been rotated 270° CCW about the origin.

Rotation

The transformation for rotation 270° CCW is the same as that for rotation 90° CW:

(x, y) ⇒ (y, -x)

For the given point, this is ...

A(1, 5) ⇒ A'(5, -1)

The image of A is A'(5, -1), choice D.