Answer:
270°
Step-by-step explanation:
For example,
(x, y) is in 1st quadrant (x- coordinate is positive, y - coordinate is positive) , then
(y, - x) is in 4th (x- coordinate is positive, y - coordinate is negative).
x and y changed places, so clockwise is 90°,
and counter-clockwise 360-90= 270°.
