angular unit การใช้

The last two angular units, plane angle and solid angle, are subsidiary units used in the SI, but are treated as dimensionless.
Today, the reference plane for an azimuth is typically true north, measured as a 0?azimuth, though other angular units ( mil ) can be used.
You don't even need to " use " radians, because the relevant relationships are independent of angular units .-- Talk 19 : 40, 21 March 2007 ( UTC)
It is thought that the ancient Chinese astronomers also used " chi " as an angular unit; modern analysis of historical records indicates that it may have been equal to one degree.
Where geographic coordinates are used as the argument of a trigonometric function, the values may be expressed in any angular units compatible with the method used to determine the value of the trigonometric function.