Detailed description
Circle with radius of 1, centre of circle at origin O. Point marked on circle in quadrant 1 as P(cos 30 degrees, sin 30 degrees). Point marked as P dash (cos 150 degrees, sin 150 degrees) in quadrant 2. Right-angled triangles POQ and P dash O Q dash drawn with angle POQ = angle P dash O Q dash = 30 degrees. Angle QOQ dash is 150 degrees.
