Question

Polygon ABCD is rotated 90º counterclockwise about the origin to create polygon A′B′C′D′. Match each set of coordinates to the vertices of polygon A′B′C′D′. Tiles A′ (-1, 3) B′ (-2, 2) C′ (-2, 1) D′ (-1, 1)

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Answer 1

Look at the picture.

Answer:

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

Answer 2

A' = (-1,3) - A = (3,11)

B' = (-2,2) - B = (2,2)

C' = (-2,1) - C = (1,2)

D' = (-1,1) - D = (1,1,)

Explanation:

We have the polygon ABCD transformed to the polygon A'B'C'D' with the co-ordinates,

A' = (-1,3), B' = (-2,2), C' = (-2,1) and D' = (-1,1).

Since, the polygon is rotated 90 counterclockwise about the origin.

The co-ordinates (x,y) of ABCD will change to (-y,x) for A'B'C'D'.

So, we will change the co-ordinates (-y,x) of A'B'C'D' to (x,y) which gives the co-ordinates of ABCD.

That is,

Take the y-value to the 1st position and x-value to the second multiplied by negative sign.

Thus, we have,

A' = (-1,3) ------------------ A = (3,1)

B' = (-2,2) ------------------ B = (2,2)

C' = (-2,1) ------------------ C = (1,2)

D' = (-1,1) ------------------- D = (1,1,)