If a rotation from the initial side to terminal side is of a revolution, the angle is said to have a measure of one degree, written as .
A degree is divided in 60 minutes and a minute is divided in 60 seconds
Some angles are shown below (In degree)
Angle subtended at the centre by an arc of length in a unit cirlce (circle of radius is said to be a measure of radian.
The circumference of a circle of radius . Thus, one complete revolution of the initial sides subtends an angle of radian.
In a circle of radius , an arc of length or subtends an angle whose measure is radian, an arc of length will subtend an angle whose measure is .
Thus, is a circle of radius , an arc length length subtends an angle radian at centre, we have
Some angles whose measures are in radian shown below:
Relation Between Degree and Radians
Convert into radian.
Find the radius of the circle in which a central angle of intercepts an arc of length
Convert radian in degree measure