#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<n;++i)

using namespace std;

typedef complex<double> C;

namespace std {
    bool operator < (const C& a, const C& b) {
        return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
    }
}

struct L : public vector<C> {
    L(const C &a, const C &b) {
        push_back(a); push_back(b);
    }
};

//??????
double cross(const C& a, const C& b) {
    return imag(conj(a)*b);
}
//??????
double dot(const C& a, const C& b) {
    return real(conj(a)*b);
}


int ccw(C a, C b, C c) {
    b -= a; c -= a;
    if (cross(b, c) > 0)   return +1;       // counter clockwise
    if (cross(b, c) < 0)   return -1;       // clockwise
    if (dot(b, c) < 0)     return +2;       // c--a--b on line
    if (norm(b) < norm(c)) return -2;       // a--b--c on line
    return 0;
}
//??´???????????????????????????(????????´??????True)
bool intersectLL(const L &l, const L &m) {
    return abs(cross(l[1]-l[0], m[1]-m[0])) > EPS || abs(cross(l[1]-l[0], m[0]-l[0])) < EPS;
}
//??´?????¨?????????????????????(????????±??????????????¨??????)
bool intersectLS(const L &l, const L &s) {
    return cross(l[1]-l[0], s[0]-l[0]) * cross(l[1]-l[0], s[1]-l[0]) < EPS;
}
//??´?????¨????????????(??±???)??????
bool intersectLP(const L &l, const C &p) {
    return abs(cross(l[1]-p, l[0]-p)) < EPS;
}
//??????????????????????????????(????????±??????????????¨??????)
bool intersectSS(const L &s, const L &t) {
    return ccw(s[0],s[1],t[0])*ccw(s[0],s[1],t[1]) <= 0 && ccw(t[0],t[1],s[0])*ccw(t[0],t[1],s[1]) <= 0;
}
//????????¨????????????(??±???)??????
bool intersectSP(const L &s, const C &p) {
    return abs(s[0]-p)+abs(s[1]-p)-abs(s[1]-s[0]) < EPS;
}
//???p?????´???l???????°???±
C projection(const L &l, const C &p) {
    double t = dot(p-l[0], l[0]-l[1]) / norm(l[0]-l[1]);
    return l[0] + t*(l[0]-l[1]);
}
//???p?????´???l????????¨??????????§°?§????
C reflection(const L &l, const C &p) {
    return p + (projection(l, p) - p)*2.0;
}
//?????¨??´???????????¢
double distanceLP(const L &l, const C &p) {
    return abs(p - projection(l, p));
}
//??´?????¨??´???????????¢
double distanceLL(const L &l, const L &m) {
    return intersectLL(l, m) ? 0 : distanceLP(l, m[0]);
}
//??´?????¨??????????????¢
double distanceLS(const L &l, const L &s) {
    if (intersectLS(l, s)) return 0;
    return min(distanceLP(l, s[0]), distanceLP(l, s[1]));
}
//????????¨???????????¢
double distanceSP(const L &s, const C &p) {
    const C r = projection(s, p);
    if (intersectSP(s, r)) return abs(r - p);
    return min(abs(s[0] - p), abs(s[1] - p));
}
//????????¨??????????????¢
double distanceSS(const L &s, const L &t) {
    if (intersectSS(s, t)) return 0;
    return min(min(distanceSP(s, t[0]), distanceSP(s, t[1])),min(distanceSP(t, s[0]), distanceSP(t, s[1])));
}
//??´???????????????????????????
C crosspoint(const L &l, const L &m) {
    double A = cross(l[1] - l[0], m[1] - m[0]);
    double B = cross(l[1] - l[0], l[1] - m[0]);
    //????????´????????¨???
    if(abs(A) < EPS && abs(B) < EPS){
        return m[0];
    }
    return m[0] + B / A * (m[1] - m[0]);
}
//?????????????????????
L crosspointSS(C p1,int r1,C p2,int r2)
{
    double d = norm(p2-p1);
    double t = r2*r2 - r1*r1 - d;
    double aa = d,bb = t*(real(p2)-real(p1)),cc = t*t / 4.0 - (imag(p2) - imag(p1))*(imag(p2) - imag(p1))*r1*r1;
    double x1 = (-bb - sqrt(bb*bb - 4*aa*cc))/(2*aa),x2 = (-bb + sqrt(bb*bb - 4*aa*cc))/(2*aa);
    double y1,y2;
    if(imag(p1) == imag(p2)){
        y1 = -sqrt(r1*r1 - x1*x1);
        y2 = -y1;
    }else{
        y1 = (t+2*(real(p2)-real(p1))*x1)/(-2*(imag(p2)-imag(p1)));
        y2 = (t+2*(real(p2)-real(p1))*x2)/(-2*(imag(p2)-imag(p1)));
    }
    L ln = L(C(x1+real(p1),y1+imag(p1)),C(x2+real(p1),y2+imag(p1)));
    return ln;
}
//??????????±???????
vector<C> convex_hull(vector<C> ps) {
    int n = ps.size(), k = 0;
    sort(ps.begin(), ps.end());
    vector<C> ch(2*n);
    for (int i = 0; i < n; ch[k++] = ps[i++]){
        while (k >= 2 && ccw(ch[k-2], ch[k-1], ps[i]) <= 0) k--;
    }
    for (int i = n-2, t = k+1; i >= 0; ch[k++] = ps[i--]){
        while (k >= t && ccw(ch[k-2], ch[k-1], ps[i]) <= 0) k--;
    }
    ch.resize(k-1);
    return ch;
}
//?????§??????
bool isconvex(const vector<C> &ps) {
    rep(i,ps.size()){
        if (ccw(ps[(i+ps.size()-1) % ps.size()],ps[i],ps[(i+1) % ps.size()])) return false;
    }
    return true;
}
//????§???¢?????¢???
double area(const vector<C> &ps) {
    double A = 0;
    rep(i,ps.size()){
        A += cross(ps[i],ps[(i+1) % ps.size()]);
    }
    return A / 2.0;
}

vector<C> convex_cut(const vector<C>& ps, const L& l){
    vector<C> Q;
    rep(i,ps.size()){
        C A = ps[i], B = ps[(i+1)%ps.size()];
        if (ccw(l[0], l[1], A) != -1){
            Q.push_back(A);
        }
        if (ccw(l[0], l[1], A)*ccw(l[0], l[1], B) < 0){
            Q.push_back(crosspoint(L(A, B), l));
        }
    }
    return Q;
}

int main()
{
    int n;
    cin >> n;
    vector<C> vec;
    rep(i,n){
        int x,y;
        cin >> x >> y;
        vec.push_back(C(x,y));
    }
    int q;
    cin >> q;
    rep(i,q){
        vector<C> res;
        int w,x,y,z;
        cin >> w >> x >> y >> z;
        res = convex_cut(vec,L(C(w,x),C(y,z)));
        printf("%.10f\n",area(res));
    }
}

Measured memory_bytes: 3208