#include <bits/stdc++.h>
using namespace std;

#define getchar getchar_unlocked

int in() {
    int n, c;
    while ((c = getchar()) < '0') if (c == EOF) abort();
    n = c - '0';
    while ((c = getchar()) >= '0') n = n * 10 + c - '0';
    return n;
}

int main() {
    int m;
    cin >> m;
    double maxi = exp(10);
    while (m--) {
        int a = in(), b = in();
        int A = in(), B = in();
        double t = A + 1e-4 * B;
        double ans = 0;
        {
            double ok = 1.1;
            double ng = 0;
            for (int ii = 0; ii < 40; ii++) {
                double mid = (ok + ng) / 2;
                if (pow(mid, a) * pow(log(mid), b) >= t) {
                    ok = mid;
                } else {
                    ng = mid;
                }
            }
            if (ok < 1 + 1e-6) {
                ans = ok;
            }
        }
        {
            double ok = maxi;
            double ng = 1;
            double logT = log(t);
            for (int ii = 0; ii < 50; ii++) {
                double mid = (ok + ng) / 2;
                double logN = log(mid);
                double loglogN = log(logN);
                if (a * logN + b * loglogN >= logT) {
                    ok = mid;
                } else {
                    ng = mid;
                }
            }
            if (ok > 1 + 1e-9) {
                ans = ok;
            }
        }
        printf("%.20f\n", ans);
    }
}