Public Function calcpi(E As Integer) As Long 
Dim pi As Double '
3.1415926535897932384626433832795028841972 
pi = 3.14159265358979 
Dim i As Long 
Dim x As Double i = 0 
Do Until Abs(pi - y) < 10 ^ -(E + 1) i = i + 1 x = x + 1 / i ^ 2 y = Sqr(x * 6) 
Loop 
calcpi = i 
End Function