What is an angle?
Published at : 05 Nov 2020
Learn about angles in trigonometry. An angle is the figure formed by two rays sharing the same endpoint. The two rays are called the sides of the angle while the common endpoint of the two rays is called the vertex of the angle.
Angle is measured in radians or in degrees. The radian is the measure of the length of an arc of a unit circle or the measure of the radius of the circle on the circumference of the circle. pi radians is equivalent to 180 degrees. One complete revolution about a point is equivalent to 2pi radians and 360 degrees. A plane is usually divided into 4 equal parts called the quadrants.
Angle measured in the anti-clockwise direction is called a positive angle while a negative angle is measured in the clockwise direction. We measure angles starting from the positive x-axis.