**Metric Angles**

A *gradian* is a metric measure of angle with 100 gradians in a right angle, and therefore 400 in a complete circle.

Also known as grades or centesimal degrees, *gradians* are not widely used in mathematics, lacking the useful and interesting properties of radians and degrees; but they are common in geodesy (surveying).

**Conversion Factors**

degrees = 9/10 × gradians

gradians = 10/9 × degrees

radians = pi/200 × gradians

gradians = 200/pi × radians

*Brought to you by the 'what does that button on my calculator do?' team*