#include using namespace std; #define rep(i,n) for(int i = 0; i < (int)n; i++) #define FOR(n) for(int i = 0; i < (int)n; i++) #define repi(i,a,b) for(int i = (int)a; i < (int)b; i++) #define pb push_back #define m0(x) memset(x,0,sizeof(x)) #define fill(x,y) memset(x,y,sizeof(x)) #define bg begin() #define ed end() #define all(x) x.bg,x.ed #define vi vector #define vvi vector #define vll vector #define vvll vector #define vs vector #define vvs vector #define vc vector #define vvc vector #define pii pair #define pllll pair #define vpii vector> #define vpllll vector> #define vpis vector> #define vplls vector> #define vpsi vector> #define vpsll vector> #define int ll using ll = long long; using ld = long double; using ull = unsigned long long; const ll INF = 1e15; void solve() { cout << fixed << setprecision(20); int t; cin >> t; while(t--) { ld r; cin >> r; cout << r * r * 3 * sqrt(3) / 4 << endl; } } signed main() { cin.tie(nullptr); ios::sync_with_stdio(false); solve(); return 0; }