#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
 
int main() {
    int t;
    cin >> t;
    rep(i,t) {
        int r;
        cin >> r;
        double ans = 1.73205080757*0.75*r*r;
        cout << ans << endl;
    }
}