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

typedef long long ll;
#define REP(i,n) for(int i=0,_n=(int)(n);i<_n;++i)
#define ALL(v) (v).begin(),(v).end()
#define CLR(t,v) memset(t,(v),sizeof(t))
template<class T1,class T2>ostream& operator<<(ostream& os,const pair<T1,T2>&a){return os<<"("<<a.first<<","<<a.second<< ")";}
template<class T>void pv(T a,T b){for(T i=a;i!=b;++i)cout<<(*i)<<" ";cout<<endl;}
template<class T>void chmin(T&a,const T&b){if(a>b)a=b;}
template<class T>void chmax(T&a,const T&b){if(a<b)a=b;}


typedef long double D;
const D PI = acos(-1.0);
const D EPS = 1e-10;
class P { public:
  D x, y;
  P(D x=0, D y=0) : x(x), y(y) {}

  P& operator+=(const P& o) { x += o.x; y += o.y; return *this; }
  P& operator-=(const P& o) { x -= o.x; y -= o.y; return *this; }
  P& operator*=(const P& o) { return *this = {x*o.x - y*o.y, x*o.y + y*o.x}; }
  P& operator*=(const D& r) { x *= r; y *= r; return *this; }
  P& operator/=(const D& r) { x /= r; y /= r; return *this; }
  P operator-() const { return {-x, -y}; }

  D norm() const { return x*x + y*y; }
  D abs() const { return sqrt(norm()); }
  D arg() const { return atan2(y, x); }
  bool isZero() const { return std::abs(x) < EPS && std::abs(y) < EPS; }
  /** 象限 */
  int orth() const { return y >= 0 ? (x >= 0 ? 1 : 2) : (x < 0 ? 3 : 4); }
  static P polar(const D& rho, const D& theta = 0) { return {rho * cos(theta), rho * sin(theta)}; }
};
std::ostream &operator<<(std::ostream &os, P const &p) { return os << "(" << p.x << ", " << p.y << ")"; }
std::istream &operator>>(std::istream &is, P &p) { D a, b; is >> a >> b; p = P(a, b); return is; }
P operator+(const P& p, const P& q) { return P(p) += q; }
P operator-(const P& p, const P& q) { return P(p) -= q; }
P operator*(const P& p, const P& q) { return P(p) *= q; }
P operator*(const P& p, const D& r) { return P(p) *= r; }
P operator/(const P& p, const D& r) { return P(p) /= r; }
P operator*(const D& r, const P& p) { return P(p) *= r; }
P operator/(const D& r, const P& p) { return P(p) /= r; }
D crs(const P& a, const P& b){ return a.x*b.y - a.y*b.x; }
D dot(const P& a, const P& b){ return a.x*b.x + a.y*b.y; }
int signum(D x) {return x > EPS ? +1 : x < -EPS ? -1 : 0;}

int ccw(const P& a, P b, P c) {
  // return signum(crs(b - a, c - a));
  b -= a; c -= a;
  if (crs(b, c) > 0)       return +1;       // counter clockwise
  if (crs(b, c) < 0)       return -1;       // clockwise
  if (dot(b, c) < 0)       return +2;       // c--a--b on line
  if (b.norm() < c.norm()) return -2;       // a--b--c on line
  return 0;
}
P intersectionLL(const P& a1, const P& a2, const P& b1, const P& b2){
  P a = a2 - a1; P b = b2 - b1;
  return a1 + a * crs(b, b1-a1) / crs(b, a);
}
// 凸多角形をある直線で切断し、左側を残す。
// 凸多角形は半時計回りに与えられていること
vector<P> convexCut(const vector<P>& ps, const P& p1, const P& p2) {
  vector<P> ret;
  int N = ps.size();
  REP(i,N){
      P a = ps[i];
      P b = ps[(i+1)%N];
      if( ccw(p1, p2, a) != -1 ) ret.push_back(a);
      if( ccw(p1, p2, a) * ccw(p1, p2, b) == -1 )
          ret.push_back( intersectionLL(a,b,p1,p2) );
  }
  return ret;
}
 double area(const vector<P> &v) {
  double ret = 0.0;
  REP(i, v.size()) ret += crs(v[i], v[(i+1) % v.size()]);
  return abs(ret / 2.0);
}

int main2() {
  int N; cin >> N;
  vector<P> ps(N);
  REP(i, N) cin >> ps[i];
  int Q; cin >> Q;
  REP(_, Q) {
    P a, b; cin >> a >> b;
    vector<P> ret = convexCut(ps, a, b);
    double ans = (double)area(ret);
    printf("%.10f\n", ans);
  }
  return 0;
}

int main() {

#ifdef LOCAL
  for (;!cin.eof();cin>>ws)
#endif
    main2();
  return 0;
}



Measured memory_bytes: 3216