In
mathematics, the
angle of rotation is a measurement of the amount, the
angle, by which a
figure is
rotated counterclockwise about a
fixed point, often the
center of a
circle. A clockwise rotation is considered a negative rotation, so that for instance a rotation of 310° (counterclockwise) can also be called a rotation of –50° (since 310°+50°=360°, a full rotation). A counterclockwise rotation of more than one complete turn is normally measured
modulo 360°, meaning that 360° is subtracted off as many times as possible to leave a non-negative measurement less than 360°.