Question

How are the coordinates of the new point found if it is rotated 180° counterclockwise? How many degrees is that equivalent to if the rotation is clockwise?
@rhr12

Answer 1

5) Here θ = 180 deg; cos(180) = -1 and sin(180) = 0
So, (x₁,y₁) = (x*-1-y*0, x*0+y*-1) = (-x,-y)