Value = ATan ( Number AS Float ) AS Float
Value = Atn ( Number AS Float ) AS Float

The Atn function is the inverse of the Tan function. It computes the arc-tangent of a number. That return value is in radians and in the range from -π/2 to π/2 radians (-90 to 90 degrees)

To convert from degrees to radians, multiply degrees by π/180. To convert from radians to degrees, multiply radians by 180/π. Or better use the Deg or Rad functions!

Example

The arctangent can be used to calculate the value for π as shown below:

There is another function Ang (alias ATan2) which takes two arguments and returns the angle correctly over 4 quadrants.