Question

Polygon ABCD is rotated 90 degrees counter loll about the origin to create polygon A' B' C' D'. Match set of coordinates to vertices of polygon A' B' C' D'

Answer 1

A (3, 1)

B (2, 2)

C (1, 2)

D (1, 1)

Explanation:

When a point is rotated 90° (90 degrees) counterclockwise about its origin, the coordinate B (x, y) transforms into B' (-y, x).

A′ (-1, 3) B′ (-2, 2) C′ (-2, 1) D′ (-1, 1)

Using the formula above B (x, y) ⇒ B' (-y, x), we have the coordinates for the polygon as:

A′ (-1, 3) ⇒ A (3, 1)

B′ (-2, 2) ⇒ B (2, 2)

C′ (-2, 1) ⇒ C (1, 2)

D′ (-1, 1) ⇒ D (1, 1)

∴ coordinates of the original polygon is given by the vertices:

A (3, 1), B (2, 2), C (1, 2), D (1, 1)