/**
 * author:  tsuyu93
 * started: 2021-07-23  21:45:38
 * 継続は力なり、雨だれ石を穿つ
 * make the impossible possible
**/

#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>

// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mpb = boost::multiprecision;
// using bint = mpb::cpp_int;
// // 仮数部が1024ビットの浮動小数点数型(TLEしたら小さくする)
// using Real = mpb::number<mpb::cpp_dec_float<1024>>;

#ifdef __HOGE__
#pragma region macro
#endif
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
using pii = pair<int, int>;
using pld = pair<ll, ld>;
using ppiii =  pair<pii, int>;
using ppiill = pair<pii, ll>;
using ppllll = pair<pll, ll>;
using pplii = pair<pli, int>;
using mii = map<int, int>;
using dll = deque<ll>;
using qll = queue<ll>;
using pqll = priority_queue<ll>;
using pqrll = priority_queue<ll, vector<ll>, greater<ll>>;
using pqrpll = priority_queue<pll, vector<pll>, greater<pll>>;
using vint = vector<int>;
using vbool = vector<bool>;
using vstr = vector<string>;
using vll = vector<ll>;
using vld = vector<ld>;
using vpll = vector<pll>;
using vvll = vector<vector<ll>>;
using vvint = vector<vector<int>>;
using vvld = vector<vector<ld>>;
using vvbool = vector<vbool>;
using vvstr = vector<vstr>;
using vvpll = vector<vector<pll>>;
template<typename T> using PQ = priority_queue<T>;
template<typename T> using PQR = priority_queue<T,vector<T>,greater<T>>;
#define REP(i,n) for(ll i=0;i<ll(n);i++)
#define REPD(i,n) for(ll i=n-1;i>=0;i--)
#define FOR(i,a,b) for(ll i=a;i<=ll(b);i++)
#define FORD(i,a,b) for(ll i=a;i>=ll(b);i--)
#define overload4(_1,_2,_3,_4,name,...) name
#define overload3(_1,_2,_3,name,...) name
#define rep1(n) for(ll dont_use_this_twice=0;dont_use_this_twice<n;++dont_use_this_twice)
#define rep2(i,n) for(ll i=0;i<n;++i)
#define rep3(i,a,b) for(ll i=a;i<b;++i)
#define rep4(i,a,b,c) for(ll i=a;i<b;i+=c)
#define rep(...) overload4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define rrep1(n) for(ll dont_use_this_twice=n;dont_use_this_twice--;)
#define rrep2(i,n) for(ll i=n;i--;)
#define rrep3(i,a,b) for(ll i=b;i-->(a);)
#define rrep4(i,a,b,c) for(ll i=(a)+((b)-(a)-1)/(c)*(c);i>=(a);i-=c)
#define rrep(...) overload4(__VA_ARGS__,rrep4,rrep3,rrep2,rrep1)(__VA_ARGS__)
#define each1(i,a) for(auto&&i:a)
#define each2(x,y,a) for(auto&&[x,y]:a)
#define each3(x,y,z,a) for(auto&&[x,y,z]:a)
#define each(...) overload4(__VA_ARGS__,each3,each2,each1)(__VA_ARGS__)
#define all1(i) begin(i),end(i)
#define all2(i,a) begin(i),begin(i)+a
#define all3(i,a,b) begin(i)+a,begin(i)+b
#define all(...) overload3(__VA_ARGS__,all3,all2,all1)(__VA_ARGS__)
#define rall1(i) (i).rbegin(),(i).rend()
#define rall2(i,k) (i).rbegin(),(i).rbegin()+k
#define rall3(i,a,b) (i).rbegin()+a,(i).rbegin()+b
#define rall(...) overload3(__VA_ARGS__,rall3,rall2,rall1)(__VA_ARGS__)
#define SUM(...) accumulate(all(__VA_ARGS__),0LL)
#define ALL(x) x.begin(),x.end() 
#define rALL(x) x.rbegin(),x.rend() 
#define SIZE(x) ll(x.size()) 
#define Sort(a) sort(all(a))
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define ULL(...) ull __VA_ARGS__;in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__;in(__VA_ARGS__)int scan(){ return getchar(); }
#define fs first
#define sc second
#define endl '\n'
#define elif else if
#define ADD_OVERFLOW(a, b) __builtin_add_overflow_p (a, b, (decltype((a)+(b))) 0)
#define SUB_OVERFLOW(a, b) __builtin_sub_overflow_p (a, b, (decltype((a)+(b))) 0)
#define MUL_OVERFLOW(a, b) __builtin_mul_overflow_p (a, b, (decltype((a)+(b))) 0)
void scan(int& a){ scanf("%d", &a); }
void scan(unsigned& a){ scanf("%u", &a); }
void scan(long& a){ scanf("%ld", &a); }
void scan(long long& a){ scanf("%lld", &a); }
void scan(unsigned long long& a){ scanf("%llu", &a); }
void scan(char& a){ do{ a = getchar(); }while(a == ' ' || a == '\n'); }
void scan(float& a){ scanf("%f", &a); }
void scan(double& a){ scanf("%lf", &a); }
void scan(long double& a){ scanf("%Lf", &a); }
void scan(vector<bool>& a){ for(unsigned i = 0; i < a.size(); i++){ int b; scan(b); a[i] = b; } }
void scan(char a[]){ scanf("%s", a); }
void scan(string& a){ cin >> a; }
template<class T> void scan(vector<T>&);
template<class T, size_t size> void scan(array<T, size>&);
template<class T, class L> void scan(pair<T, L>&);
template<class T, size_t size> void scan(T(&)[size]);
template<class T> void scan(vector<T>& a){ for(auto&& i : a) scan(i); }
template<class T> void scan(deque<T>& a){ for(auto&& i : a) scan(i); }
template<class T, size_t size> void scan(array<T, size>& a){ for(auto&& i : a) scan(i); }
template<class T, class L> void scan(pair<T, L>& p){ scan(p.first); scan(p.second); }
template<class T, size_t size> void scan(T (&a)[size]){ for(auto&& i : a) scan(i); }
template<class T> void scan(T& a){ cin >> a; }
template <typename T> std::istream &operator>>(std::istream &is, std::vector<T> &a) {for (auto &x : a) is >> x;return is;}
template <typename T1, typename T2> std::istream &operator>>(std::istream &is, std::pair<T1,T2> &a) { is >> a.first >> a.second; return is;}
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){ scan(head); in(tail...); }
void print(){ putchar(' '); }
void print(bool a){ printf("%d", a); }
void print(int a){ printf("%d", a); }
void print(unsigned a){ printf("%u", a); }
void print(long a){ printf("%ld", a); }
void print(long long a){ printf("%lld", a); }
void print(unsigned long long a){ printf("%llu", a); }
void print(char a){ printf("%c", a); }
void print(char a[]){ printf("%s", a); }
void print(const char a[]){ printf("%s", a); }
void print(float a){ printf("%.15f", a); }
void print(double a){ printf("%.15f", a); }
void print(long double a){ printf("%.15Lf", a); }
void print(const string& a){ for(auto&& i : a) print(i); }
template<typename T1, typename T2>ostream &operator<<(ostream &os, const pair<T1, T2>&p){return os << p.first << " " << p.second;}
template<class T> void print(const complex<T>& a){ if(a.real() >= 0) print('+'); print(a.real()); if(a.imag() >= 0) print('+'); print(a.imag()); print('i'); }
template<class T> void print(const vector<T>&);
template<class T, size_t size> void print(const array<T, size>&);
template<class T, class L> void print(const pair<T, L>& p);
template<class T, size_t size> void print(const T (&)[size]);
template<class T> void print(const vector<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<class T> void print(const deque<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<class T, size_t size> void print(const array<T, size>& a){ print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<class T, class L> void print(const pair<T, L>& p){ print(p.first); putchar(' '); print(p.second); }
template<class T, size_t size> void print(const T (&a)[size]){ print(a[0]); for(auto i = a; ++i != end(a); ){ putchar(' '); print(*i); } }
template<class T> void print(const T& a){ cout << a; }
int out(){ putchar('\n'); return 0; }
template<class T> int out(const T& t){ print(t); putchar('\n'); return 0; }
template<class Head, class... Tail> int out(const Head& head, const Tail&... tail){ print(head); putchar(' '); out(tail...); return 0; }
template <class T> vector<T> make_vec(size_t a, T b) {return vector<T>(a,b);}
template <class T, class... Ts> auto make_vec(size_t a, Ts... ts) {return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));}
#ifdef DEBUG
#define debug(...) { print(#__VA_ARGS__); print(":"); out(__VA_ARGS__); }
#else
#define debug(...) void(0)
#endif
template<typename T,typename E>pair<T,E>& operator+=(pair<T,E>&s,const pair<T,E>&t){s.first+=t.first;s.second+=t.second;return s;}
template<typename T,typename E>pair<T,E>& operator-=(pair<T,E>&s,const pair<T,E>&t){s.first-=t.first;s.second-=t.second;return s;}
template<typename T,typename E>pair<T,E> operator+(const pair<T,E>&s,const pair<T,E>&t){auto res=s;return res+=t;}
template<typename T,typename E>pair<T,E> operator-(const pair<T,E>&s,const pair<T,E>&t){auto res=s;return res-=t;}
template<typename T>T poll(queue<T> &q){auto ret=q.front();q.pop();return ret;}
template<typename T>T poll(deque<T> &q){auto ret=q.front();q.pop_front();return ret;}
template<typename T>T poll(priority_queue<T> &q){auto ret=q.top();q.pop();return ret;}
template<typename T>T poll(PQR<T> &q){auto ret=q.top();q.pop();return ret;}
template<typename T>T poll(stack<T> &s){auto ret=s.top();s.pop();return ret;}
#define INF32 2147483647 //2.147483647x10^{9}:32bit整数のinf
#define INF64 9223372036854775807 //9.223372036854775807x10^{18}:64bit整数のinf
const ll MOD = 1000000007;
// const ll MOD = 998244353;
const int inf = 1e9;
const ll INF = (1LL<<61);
const ll MAXR = 100000; //10^5:配列の最大のrange
const ld PI = acos(-1);
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n - 1); }
inline void Yes(bool b = true) { cout << (b ? "Yes" : "No") << '\n'; }
inline void YES(bool b = true) { cout << (b ? "YES" : "NO") << '\n'; }
inline void OKNG(bool b = true) { cout << (b ? "OK" : "NG") << '\n'; }
inline void GAme(bool b = true) { cout << (b ? "First" : "Second") << '\n'; }
inline void gAme(bool b = true) { cout << (b ? "first" : "second") << '\n'; }
inline void Takahashi_Aoki(bool b = true) { cout << (b ? "Takahashi" : "Aoki") << '\n'; }
inline void takahashi_aoki(bool b = true) { cout << (b ? "takahashi" : "aoki") << '\n'; }
inline void possible(bool i = true){ cout << (i?"possible":"impossible") << '\n'; }
inline void Possible(bool i = true){ cout << (i?"Possible":"Impossible") << '\n'; }
inline void POSSIBLE(bool i = true){ cout << (i?"POSSIBLE":"IMPOSSIBLE") << '\n'; }
template<typename T1,typename T2>void print_with_bool(bool x,T1 y,T2 z){if(x)cout<<y<<endl;else cout<<z<<endl;}
template<typename A, typename B> inline bool chmin(A& a, B b) {if (a > b) {a = b;return true;}return false;}
template<typename A, typename B> inline bool chmax(A& a, B b) {if (a < b) {a = b;return true;}return false;}
template<class T> auto min(const T& a){ return *min_element(a.begin(),a.end()); }
template<class T> auto max(const T& a){ return *max_element(a.begin(),a.end()); }
template<typename T> T power(T a, T b) {T res=1;while (b>0) {if (b&1){res*=a;}b/=2;a*=a;}return res;}
long long powmod(long long a, long long b) {long long res=1;while (b>0) {if (b&1){res*=a;res%=MOD;}b/=2;a*=a;a%=MOD;}return res;}
template<typename T> T powmod(T a, T b,T m) {T res=1;while (b>0) {if (b&1){res*=a;res%=m;}b/=2;a*=a;a%=m;}return res%m;}
template<typename T> T nlcm(const vector<T> &a) {T res;res = a[0];for (ll i = 1; i < (ll)a.size(); i++) {res = lcm(res, a[i]);}return res;}
template<typename T> T ngcd(const vector<T> &a){T res;res = a[0];for(ll i = 1; i < (ll)a.size() && res != 1; i++) {res = gcd(a[i], res);}return res;}
template<typename T> T sqr(T x){T r=sqrt(x)-1;while((r+1)*(r+1)<=x)r++;return r;}
template<typename T> T bit_length(T a){T k = 0;while(a){k++;a/=2;}return k;}
template<typename T> T isqrt(T n){T a = 0, r = 0;for(T s = bit_length(n)-(bit_length(n)%2?1:2); s >= 0;s-=2){T t = ((n >> s) & 3);r = ((r << 2) | t);T c = ((a << 2) | 1);int b = (r >= c);if(b){r -= c;}a = ((a << 1) | b);}return a;}
int popcount(long long a){return __builtin_popcountll(a);}
int popcount(int a){return __builtin_popcount(a);}
int poplow(ll x){return __builtin_ctzll(x);}
int poplow(int x){return __builtin_ctz(x);}
int pophigh(ll x){return 63 - __builtin_clzll(x);}
int pophigh(int x){return 31 - __builtin_clz(x);}
template<typename T> T ceil(T a, T b) {if(b < 0) a = -a, b = -b;return (a >= 0 ? (a + b - 1) / b : a / b);}
template<typename T> T floor(T a, T b) {if(b < 0) a = -a, b = -b;return (a >= 0 ? a / b : (a - b + 1) / b);}
template<typename T> T sum_of_digit(T a) {T res = 0;while(a){res += a%10; a /= 10;}return res;}
template<typename T ,typename A> void add_edge(vector<vector<T>> &G, A a, A b,bool directed = false){G[a].emplace_back(b);if(!directed)G[b].emplace_back(a);}
template<typename T ,typename A> void add_edge(vector<vector<pair<T,T>>> &G, A a, A b, A p,bool directed = false){G[a].emplace_back(p,b);if(!directed)G[b].emplace_back(p,a);}
#ifdef __HOGE__
#pragma endregion
#endif

// #include<atcoder/all>
// using namespace atcoder;
// using mint = modint1000000007;
// using mint = modint998244353;
// using vm = vector<mint>;
// using vvm = vector<vm>;

#include <iostream>
#include <cmath>
#include <iomanip>
#include <vector>

const double EPS = 1e-8;
inline bool eq(double a, double b) { return fabs(b - a) < EPS; }

struct Point{
    double x, y;
    Point(): x(0), y(0) {}
    Point(double _x, double _y): x(_x), y(_y) {}
    Point operator+(const Point &b) const { return Point(x + b.x, y + b.y); }
    Point operator-(const Point &b) const { return Point(x - b.x, y - b.y); }
    Point operator*(const double b) const { return Point(x * b, y * b); }
    Point operator*(const Point &b) const { return Point(x * b.x - y * b.y, x * b.y + y * b.x); }
    Point operator/(const double b) const { return Point(x / b, y / b); }
    bool operator==(const Point &b) const { return eq(x, b.x) && eq(y, b.y); }
    bool operator<(const Point &b) const { return x != b.x ? x < b.x : y < b.y; }
    double cross(Point b){return this->x * b.y - this->y * b.x;}//外積
    double dot(Point b){return this->x * b.x + this->y * b.y;} //内積
    double distance(Point v){return sqrt((this->x - v.x)*(this->x - v.x) + (v.y - this->y)*(v.y - this->y));}
    double abs(){return sqrt(x * x + y * y);}
    double abs2(){return x * x + y * y;}
    double arg() { return atan2(y, x); }
    Point rotate(double theta) { return Point(cos(theta) * x - sin(theta) * y, sin(theta) * x + cos(theta) * y); }
    Point rotate90() { return Point(-y, x); }
    friend ostream &operator<<(ostream &os, Point &p) { return os << "(" << p.x << "," << p.y << ")"; }
    friend istream &operator>>(istream &is, Point &a) { return is >> a.x >> a.y; }
};

double RadianToDegree(double r){
  return (r * 180.0 / acos(-1));
}

double DegreeToRadian(double d){
  return (d * acos(-1) / 180.0);
}

double area(std::vector<Point> vec){
    int n = vec.size();
    if(n <= 2) return 0;
    double res = 0;
    for(int i = 1; i < n; i++){
        res += (vec[i].x - vec[i - 1].x) * (vec[i].y + vec[i - 1].y);
    }
    res += (vec[0].x - vec[n - 1].x) * (vec[0].y + vec[n - 1].y);
    return std::abs(res) / 2;
}

void main_(){
   
    cout << fixed << setprecision(15);

    double R;
    cin >> R;
    vector<Point>  vec;
    Point a = {0,R};
    Point b = a.rotate(DegreeToRadian(120));
    Point c = b.rotate(DegreeToRadian(120));

    vec = {a,b,c};

    cout << area(vec) << endl;

    //cout << ans << endl;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
   int t = 1;
   cin >> t;
   while(t--) main_();
   return 0;
}