#include<bits/stdc++.h>
using namespace std;

int main() {
  constexpr long double sqrt3 = sqrt(3);
  int n;
  cin >> n;
  for(int i = 0; i < n; ++i) {
    int a;
    cin >> a;
    a *= a;
    printf("%.15Lf\n", (a*3*sqrt3)/4);
  }
}