using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static void Main()
    {
        var t = NN;
        var res = new decimal[t];
        for (var u = 0; u < t; ++u)
        {
            var c = ReadLine().Split();
            var (T, m, L) = (decimal.Parse(c[0]), decimal.Parse(c[1]), decimal.Parse(c[2]));
            var ng = (decimal)5101;
            var ok = (decimal)0;
            while (ng - ok > (decimal)0.0001)
            {
                var v = (ok + ng) / 2;
                if (v * T + v * v / 20 / m <= L) ok = v;
                else ng = v;
            }
            res[u] = ok;
        }
        WriteLine(string.Join("\n", res.Select(r => string.Format("{0:0.00}", Math.Floor(r * 360) / 100))));
    }
}