Question

Select the correct answer.

If quadrilateral ABCD rotates 90° counterclockwise about the origin, what are the coordinates of A′ in quadrilateral A′B′C′D′ ?

A.
(2, 1)

B.
(-2, -1)

C.
(-2, -2)

D.
(-2, 0)

Answer 1

A' (-1, 2)

Explanation:

(x, y) -> (-y, x)

A' (-1, 2)

B' (1, -2)

C' (2, -2)

D' (0, -2)

Answer 2

The coordinates of A′ in quadrilateral A′B′C′D′ are b. (2, -1)

How to deterimine the coordinates of A′ in quadrilateral A′B′C′D′ ?

From the question, we have the following parameters that can be used in our computation:

The quadrilateral ABCD

On the figure, we have the coordinates of the point A to be

A = (-1, 2)

Also, we have the rule of transformation to be

Rotation by 90° counterclockwise about the origin

Mathematically, this is represented as

(x, y) ⇒ (-y, x)

Given that

A = (-1, 2)

Then

A' = (-2, -1)

Hence, the coordinates of A′ are (-2, -1)

Question

If quadrilateral ABCD rotates 90° counterclockwise about the origin, what are the coordinates of A′ in quadrilateral A′B′C′D′ ?

A. (2, 1) B. (-2, -1) C. (-2, -2) D. (-2, 0)