Question

Which ordered pair gives the coordinates of the image of R(-a, b) if R is rotated clockwise 180°?

(b, -a)
(a, -b)
(-b, -a)
(a, b)

Answer 1

The correct answer is:

(a, -b)

Step-by-step explanation:

A 180° rotation maps every point (x, y) to (-x, -y). This means that both the x- and y-coordinates are negated.

For the point R(-a, b), this means that both coordinates are negated; this gives us R'(a, -b).

Answer 2

Rule for a clockwise rotation of 180 is

`r_(180)(x,y) \rightarrow (-x,-y)`


`r_(180)R(-a,b) \rightarrow R'(a,-b)`