program ABC144D
    implicit none
    real::a,b,x
    read*,a,b,x

    if(x>=a*a*b/2)then
        print'(f0.10)',atan(2*(a*a*b-x)/(a*a*a))*180/3.14159265358
    else
        print'(f0.10)',atan(a*b*b/(2*x))*180/3.14159265358
    end if
end program ABC144D