      PROGRAM waterBottle
      IMPLICIT NONE
      REAL(8) :: a,b,x
      REAL(8) :: theta,V
      REAL(8) :: pi = 3.141592653589793238
      
      READ*,a,b,x
      
      V = a*a*b
      if( x>=V/2. )THEN
       ! theta = atan( a**3/(2.*x) )
        theta = atan( a**2/2./(a*b-x/a) )
      ELSE
        !theta = atan( 2./(b*b)*(a*b-x/a) )
        theta = atan( 2.*x/(b**2*a) )
      END IF
      
      print*,  90.-theta*180./pi
      
      
      END PROGRAM