Question

what is the difference between 0 degree angle and 180 degree angle

Answer 1

Degrees mean division of a circle and not a line. If you are dividing a line it will be in metres, cm and inches. The division of the circle, is measured by the amount of rotation undergone by an arm attached to the pivot and turned about the pivot. The measure is taken as along the West-East (pivot - tip of arm) line or the x-axis (positive) as the reference line. The rotation is effected counterclockwise. As the arm moves away from the x-axis, the arm undergoes an increasing rotation, termed as an angle. When the arm is West- East (pivot - tip of arm), it is termed 0 degrees and when it is East-West (pivot - tip of arm), it is termed 180 degrees.

Zero degrees means the end of the arm is pointing towards the East and 180 degrees means the end of the arm is pointing towards the West. We follow a common practice so that the person explaining and the listener are on the same wavelength and they follow what either means when explaining some mathematical concept to the audience.