/*
 * CIRCLE_E.c
 *
 *  Created on: Mar 6, 2014
 *      Author: Arpit Bhayani
 */

/**
 * http://en.wikipedia.org/wiki/Descartes'_theorem
 * The larger a circle, the smaller is the magnitude of its curvature, and vice versa.
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define DEBUG 0

int readline(char * str) {

    int i = 0;
    char ch;
    while ((ch = getchar()) != '\n') {
        str[i++] = ch;
    }
    str[i] = '\0';
    return i;
}

int main(int argc, char * argv[]) {

    int t;
    scanf("%d", &t);
    while (t--) {

        double r1, r2, r3;
        double curvature1, curvature2, curvature3;

        double curvature4, r4;

        scanf("%lf%lf%lf", &r1, &r2, &r3);

        curvature1 = 1 / r1;
        curvature2 = 1 / r2;
        curvature3 = 1 / r3;

        curvature4 = curvature1 + curvature2 + curvature3
                + 2
                        * sqrt(
                                curvature1 * curvature2
                                        + curvature2 * curvature3
                                        + curvature3 * curvature1);

        r4 = 1/curvature4;

        printf("%.6lf\n" , r4);
    }

    return 0;
}