C# 3.0 Cookbook, 3rd Edition

20.1. Converting Between Degrees and Radians

Problem

When using the trigonometric functions of the Math class, all units are in radians. You have some angles measured in degrees and want to convert these to radians in order to use them with the members of the Math class, and some angles measured in radians that need to be in degrees.

Solution

To convert a value in degrees to radians, multiply it by math.PI/180:

	using System;

	public static double ConvertDegreesToRadians (double degrees)
	{
	    return ((Math.PI / 180) * degrees);
	}

To convert a value in radians to degrees, multiply it by 180/mathPI:

	using System;

	public static double ConvertRadiansToDegrees(double radians)
	{
	    return ((180 / Math.PI) * radians);
	}

Discussion

All of the static trigonometric methods in the Math class use radians as their unit of measure for angles. It is very handy to have conversion routines to convert between radians and degrees, especially when a user is required to enter data in degrees rather than radians. After all, humans understand degrees better than radians.

The static field Math.PI contains the constant 3.14151265358979323846.