Question

the point p (-1,2) is rotated to become p (2,1). describe the rotation by degree and direction. (1 point)
90° rotation
180° rotation
-90° rotation
-270° rotation

Explanation:

Step1: Recall rotation rules

For a 90 - degree counter - clockwise rotation about the origin, the transformation rule for a point $(x,y)$ is $(-y,x)$. For a 180 - degree rotation about the origin, the rule is $(-x,-y)$. For a 90 - degree clockwise (or - 90 - degree counter - clockwise) rotation about the origin, the rule is $(y, - x)$. For a 270 - degree clockwise (or - 270 - degree counter - clockwise) rotation about the origin, the rule is $(-y,x)$.

Step2: Apply rules to point $P(-1,2)$

If we consider a 90 - degree clockwise (or - 90 - degree counter - clockwise) rotation of the point $P(-1,2)$ using the rule $(y,-x)$, we substitute $x=-1$ and $y = 2$. We get $(2,1)$ which is $P'$.

Answer:

C. $-90^{\circ}$ rotation