
def solve
    a, b, x = gets.split.map(&:to_f)

    width = a
    init_height = x / a / a

    diff = b - init_height

    triangle_height = 2 * diff
    triangle_base = width
    if diff > init_height
        triangle_base = (a * init_height) / b
    end
    triangle_hyp = Math.sqrt(triangle_height ** 2 + triangle_base ** 2)
    res = triangle_height / triangle_base
    # p [triangle_base, triangle_height, triangle_hyp]
    puts Math.atan(res) * 180 / Math::PI
end

solve