let () =
    let main () =
        let a, b, x = Scanf.sscanf (read_line ()) "%d %d %d" (fun a b x -> a, b, x) in
        let flag = x * 2 >= a * a * b in
        let a = float a in
        let b = float b in
        let x = float x in
        let x = x /. a in
        let ans = if flag then (
            let m = 2. *. (b -. x /. a) in
            atan2 m a /. 3.141592653589793238 *. 180.
        ) else (
            let m = 2. *. x /. b in
            atan2 b m /. 3.141592653589793238 *. 180.
        )
        in
        Printf.printf "%.10f\n" ans

    in
    main ()