#include<stdio.h>#include<string.h>#include<algorithm>#include<math.h>using namespace std;double h,H,D;double f(double x){ return h*(D+x)/H-x+(H*x)/(D+x);}double BS(){ double l=0,r=D*h/(H-h),mid1,mid2; int tim=60; while(tim--) {mid1=l+(r-l)/3;mid2=r-(r-l)/3;if(f(mid1)>f(mid2)) r=mid2;else l=mid1; } return f(l);}int main(){ int t; scanf("%d",&t); while(t--) {scanf("%lf%lf%lf",&H,&h,&D);double ans=D*h/H;double tt=BS();ans=max(ans,tt);printf("%.3lfn",ans); }}
