#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll=long long;
using Graph=vector<vector<pair<int,int>>>;
#define MAX 100
#define MOD 998244353
#define INF 1000000000

int main(){
  int t;
  cin>>t;
  for(int i=0;i<t;i++){
    double r;
    cin>>r;
    double a=r/2.0*sqrt(3);
    double ans=2.0*a*sqrt(3)*a/2.0;
    printf("%.6lf\n",ans);
  }
}