program main
  implicit none
  integer :: a, b, x
  real(8) :: theta, p, q, pi
  pi = acos(-1.0d0)
  read (*, *) a, b, x
  if (2 * x >= a * a * b) then
    p = 2.0d0 * b - 2.0d0 * x / a ** 2
    theta = atan2(p, dble(a))
  else
    q = 2.0d0 * x / (a * b)
    theta = atan2(dble(b), q)
  end if
  write (*, "(f12.8)") theta * 180.0d0 / pi
  contains
end program main
