#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>


using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
#define rep(i,n) for(int i=0; i<(int)(n); i++)


const i64 INF = 1001001001001001001;
using modint = atcoder::static_modint<1000000007>;



i64 get_100I(){
    double res; cin >> res;
    res = res * 100;
    return res + 0.5;
}

bool comp_T(i64 v, i64 t, i64 m, i64 l){
    return (v * t * m * 20 + v * v) <= l * m * 20 * 10000;
}

int main(){
    int N; cin >> N;
    while(N --> 0){
        i64 t, mu, l;
        t = get_100I();
        mu = get_100I();
        l = get_100I();
        i64 lv = 0, rv = 500000000;
        while(lv + 1 < rv){
            i64 x = (lv + rv) / 2;
            if(comp_T(x, t, mu, l)) lv = x; else rv = x;
        }
        i64 ans = lv * 36 / 1000;
        cout << (ans / 100) << "." << (ans / 10 % 10) << (ans % 10) << '\n';
    }
    return 0;
}


struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;