Angle of measure 240° :
Let m∠XOA = 240° Its terminal arm (ray OA) intersects the standard unit circle at P(x, y).
Draw seg PM perpendicular to the X-axis.
ΔOMP is a 30° – 60° – 90° triangle.
OP = 1
Since point P lies in the 3rd quadrant, x < 0, y < 0
