You can simply use trigonometry to get the exact value of PI.
Examples:
rem The angle corresponding to an
rem x-coordinate(cosine) on the unit
rem circle is PI.
PI# = acos(-1)
You can use arc tangent too, except there is no direct value that gives a value of PI because the tangent curve is not defined at PI. You can, however, get a value like PI/4 then multiply by 4 to get PI.
PI/4 = atan(1)
Thus,
PI# = atan(1) * 4
These are exact values for PI, obtained without having to hard code.
NOTE: PI = asin(0), BUT asin(0) also equals 0, 2PI, 3PI, 4PI...and so on, so it may not be reliable. I have not tested asin(0) in DB yet, but in C++ asin(0) = 0, generally, as it could change from compiler to compiler.