@MrWho Just draw a circle with centre at the point the angle is formed. Then consider the ratio of the arc subtended by the angle and the circumference of the circle. Multiply this by 360 degrees and you get your angle. This is independent of the radius of the circle.
The gradian is a unit of plane angle, equivalent to 1⁄400 of a turn.
It is also known as gon, grad, or grade. One grad equals 9⁄10 of a degree or π⁄200 of a radian. In continental Europe, the French term centigrade was in use for one hundredth of a grad, and the term myriograde was in use for one ten-thousandth of a grad. This was one reason for the adoption of the term Celsius to replace centigrade as the name of the temperature scale.
== History ==
The unit originated in France as the grade, along with the metric system. Due to confusion with existing grad(e) units of northern Europe, the name...