Triangle.

#include <bits/stdc++.h>

bool checkValidity(int a, int b, int c)
{
    if (a + b <= c || a + c <= b || b + c <= a)
        return false;
    else
        return true;
}
using namespace std;
int main () {
     int i,N;
     double area,s;
     double a,b,c;
     cin>>N;
     for(int i=1;i<=N;i++){
     cin>>a>>b>>c;

      if (checkValidity(a, b, c)){
 s=(a+b+c)/2;
     area=sqrt(s *(s-a)*(s-b)*(s-c));
      printf("%.2lf\n",area);
      }

    else
      printf("Oh, No!\n");

     }
}