# Measurement of angles in Radians and Degrees

**Radian System**

In the radian system of angular measurement, the measure of one revolution is 2Ï€.

Thus half a circle, then, is Ï€. And, therefore, each right angle is half of Ï€ i.e.

Three right angles will be 3.

Five right angles will be and so on (Please refer the figure on the right hand side)

# Radians into Degrees

Here are certain examples that are used very frequently

is half of , a right angle, and so it is equal to 45Â°.

is one-third of Ï€, and so is equal to 180Â°/ 3 = 60Â°.

is one-sixth of Ï€, and so is equal to 180Â°/ 6 = 30Â°.

= 5. = 5 **x** 45Â° = 225Â°

is one-third of 2Ï€, and so is equal to one-third of a revolution i.e. 360Â°/ 3 = 120Â°.