#include<bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){
    int N;cin >> N;
    while(N--){
        string _T, _u, _L;
        cin >> _T >> _u >> _L;
        _T.erase(find(_T.begin(), _T.end(), '.'));
        _u.erase(find(_u.begin(), _u.end(), '.'));
        _L.erase(find(_L.begin(), _L.end(), '.'));

        ll T = stoi(_T);
        ll u = stoi(_u);
        ll L = stoi(_L);

        ll ok = 0;
        ll ng = 100000000;
        while(ng - ok > 1){
            ll mid = (ok + ng) / 2;
            if(L * (20 * u) * 360 * 360 >= mid * T * (2 * u) * 36 + mid * mid){
                ok = mid;
            }else{
                ng = mid;
            }
        }
        ll V = ok / 100;
        printf("%lld.%02lld\n", V / 100, V % 100);
    }
    return 0;
}