using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Numerics;
using System.Globalization;
namespace Solver
{
class Program
{
const int M = 1000000007;
const double eps = 1e-9;
static void Main()
{
var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
var sc = new Scan();
int t = sc.Int;
for (int i = 0; i < t; i++)
{
int h, w;
sc.Multi(out h, out w);
var p = 2 / Math.Sqrt(3);
if (h > w * p)
{
sw.WriteLine(Math.Sqrt(Math.Pow(h / 2.0, 2) + w * w));
continue;
}
if (w > h * p)
{
sw.WriteLine(Math.Sqrt(Math.Pow(w / 2.0, 2) + h * h));
continue;
}
double l = 0, r = w;
while (r - l > eps)
{
var m = (r + l) / 2;
var y = Math.Sqrt(h * h + m * m - w * w);
if (Math.Pow(w - m, 2) + Math.Pow(h - y, 2) < h * h + m * m)
r = m;
else
l = m;
}
sw.WriteLine(Math.Sqrt(h * h + l * l));
}
sw.Flush();
}
}
class Scan
{
public int Int { get { return int.Parse(Console.ReadLine().Trim()); } }
public long Long { get { return long.Parse(Console.ReadLine().Trim()); } }
public string Str { get { return Console.ReadLine().Trim(); } }
public int[] IntArr { get { return Console.ReadLine().Trim().Split().Select(int.Parse).ToArray(); } }
public int[] IntArrWithSep(char sep) { return Console.ReadLine().Trim().Split(sep).Select(int.Parse).ToArray(); }
public long[] LongArr { get { return Console.ReadLine().Trim().Split().Select(long.Parse).ToArray(); } }
public double[] DoubleArr { get { return Console.ReadLine().Split().Select(double.Parse).ToArray(); } }
public string[] StrArr { get { return Console.ReadLine().Trim().Split(); } }
public List<int> IntList { get { return Console.ReadLine().Trim().Split().Select(int.Parse).ToList(); } }
public List<long> LongList { get { return Console.ReadLine().Trim().Split().Select(long.Parse).ToList(); } }
public void Multi(out int a, out int b) { var arr = IntArr; a = arr[0]; b = arr[1]; }
public void Multi(out int a, out int b, out int c) { var arr = IntArr; a = arr[0]; b = arr[1]; c = arr[2]; }
public void Multi(out int a, out int b, out int c, out int d) { var arr = IntArr; a = arr[0]; b = arr[1]; c = arr[2]; d = arr[3]; }
public void Multi(out int a, out string b) { var arr = StrArr; a = int.Parse(arr[0]); b = arr[1]; }
public void Multi(out int a, out int b, out string c) { var arr = StrArr; a = int.Parse(arr[0]); b = int.Parse(arr[1]); c = arr[2]; }
public void Multi(out int a, out char b) { var arr = StrArr; a = int.Parse(arr[0]); b = arr[1][0]; }
public void Multi(out char a, out int b) { var arr = StrArr; a = arr[0][0]; b = int.Parse(arr[1]); }
public void Multi(out long a, out long b) { var arr = LongArr; a = arr[0]; b = arr[1]; }
public void Multi(out long a, out int b) { var arr = LongArr; a = arr[0]; b = (int)arr[1]; }
public void Multi(out string a, out string b) { var arr = StrArr; a = arr[0]; b = arr[1]; }
}
class mymath
{
int M;
const double eps = 1e-9;
public mymath(int M) { this.M = M; }
public long pow(long a, long b)
{
if (b == 0) return 1;
if (b == 1) return a % M;
long t = pow(a, b / 2);
if ((b & 1) == 0) return t * t % M;
else return t * t % M * a % M;
}
public long gcd(long a, long b)
{
while (b != 0)
{
var t = a % b;
a = b;
b = t;
}
return a;
}
public long lcm(int a, int b) { return (a * b) / gcd(a, b); }
}
}