program problemD
  implicit none

  integer, parameter     :: double = selected_real_kind ( 9 )
  integer, parameter     :: i8 = selected_int_kind  ( 18 )
  real ( kind = double ), parameter :: pi = 3.141592653589790_double
  integer ( kind = i8 )  :: a, b, x
  real ( kind = double ) :: ans

  read *, a, b, x
  a = real ( a )
  b = real ( b )
  x = real ( x )

  if ( a **2.0_double * b / 2.0_double < x ) then
     ans = atan ( ( 2.0_double * b ) / a - ( 2.0_double * x ) &
          & / ( a **3.0_double ) ) / ( 2.0_double * pi ) * 360_i8
  else
     ans = atan ( a * b **2.0_double / ( 2.0_double * x ) ) / ( 2.0_double * pi ) * 360_i8
  end if
  print *, ans

end program problemD
