#include <bits/stdc++.h>
#include <cmath>
using namespace std;
int main()
{
int tc;
cin>>tc;
while (tc) {
double ha, hb, hc,a,b,c;//s,s1,a1,b1,c1,a,b,c;
scanf("%lf%lf%lf", &ha, &hb, &hc);
a=1/ha,b=1/hb,c=1/hc;
double s1=(a + b + c);
double a1=(-a + b + c);
double b1=(a - b + c);
double c1=(a + b - c);
double s=s1*a1*b1*c1;
if (s <= 0)
{
printf("These are invalid inputs!\n");
tc--;
}
else if (ha == 0 || hb == 0 || hc == 0)
{
printf("These are invalid inputs!\n");
tc--;
}
else {
printf("%.3f\n", 1 / sqrt(s));
}
}
return 0;
}
