#include <bits/stdc++.h>
using namespace std;
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
#include <atcoder/all>
using namespace atcoder;
#pragma GCC optimize("O0")
typedef long long int ll;
typedef long double ld;
const ll mod = 1e9+7;
const ll INF = 1e18;
#define rep(i,n) for (ll i = 0; i < (n); ++i)
#define Rep(i,a,n) for (ll i = (a); i < (n); ++i)
#define All(a) (a).begin(),(a).end()
#define Pi acos(-1)
using Graph = vector<vector<ll>>;
using V = vector<ll>;
using P = pair<ll,ll>;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << setprecision(15) << fixed;
  }
} iosetup;

int main() {
  ll t;
  cin >> t;
  while(t--) {
    ld a;
    cin >> a;
    cout << a*a*sqrt(3)*3/4.0 << '\n';
  }
}