#include <algorithm>
#include <cmath>
#include <cstdio>
#include <iostream>
#include <vector>

using namespace std;

const double EPS = 1e-9;
const double PI = acos(-1);

int sign(double x) {
    if (fabs(x) < EPS) {
        return 0;
    } else if (x > 0) {
        return 1;
    } else {
        return -1;
    }
}

int dcmp(double x, double y) {
    return sign(x - y);
}

struct Vector;
typedef Vector Point;

struct Vector {
    double x;
    double y;

    explicit Vector(double x = 0, double y = 0);

    Vector operator+(const Vector &rhs) const;
    Vector operator-() const;
    Vector operator-(const Vector &rhs) const;
    Vector operator*(double d) const;
    Vector operator/(double d) const;
    double operator*(const Vector &rhs) const;
    double operator^(const Vector &rhs) const;

    bool operator==(const Vector &rhs) const;
    bool operator!=(const Vector &rhs) const;
    bool operator<(const Vector &rhs) const;
    bool operator>(const Vector &rhs) const;
    bool operator<=(const Vector &rhs) const;
    bool operator>=(const Vector &rhs) const;

    friend std::ostream &operator<<(std::ostream &os, const Vector &vector);

    double dot(const Vector &rhs) const;
    double cross(const Vector &rhs) const;
    double length() const;
    double length2() const;
    double angle() const;
    double angle(const Vector &rhs) const;
    Vector rotate(double rad) const;
    Vector rotate90() const;
    Vector rotate90R() const;
    Vector normal() const;
    Vector truncate(double d) const;
    double getDistanceTo(const Point &p) const;

    static bool cmpByAngle(const Vector &a, const Vector &b);
};

struct Line {
    Point a;
    Point b;

    explicit Line(double x1 = 0, double y1 = 0, double x2 = 0, double y2 = 0);
    explicit Line(const Point &a = Point(), const Point &b = Point());

    double getDistanceTo(const Point &p) const;
    Point getIntersection(const Line &rhs) const;
    Point getProjection(const Point &p) const;
    Point getReflection(const Point &p) const;
    bool contains(const Point &p) const;
    bool intersects(const Line &rhs) const;
    bool parallels(const Line &rhs) const;
    bool isPerpendicularTo(const Line &rhs) const;
};

struct Polygon {
    std::vector<Point> points;

    enum class ContainsPoint {
        OUT,
        ONLINE,
        ON_VERTEX,
        IN
    };

    explicit Polygon(const std::vector<Point> &points = std::vector<Point>(0));

    Point &operator[](const int index);

    int size() const;
    double area() const;
    double circumference() const;
    Polygon cutByHalfPlane(const Line &l) const;
};

Vector::Vector(double x, double y) : x(x), y(y) {}

Vector Vector::operator+(const Vector &rhs) const {
    return Vector(x + rhs.x, y + rhs.y);
}

Vector Vector::operator-() const {
    return Vector(-x, -y);
}

Vector Vector::operator-(const Vector &rhs) const {
    return *this + -rhs;
}

Vector Vector::operator*(double d) const {
    return Vector(x * d, y * d);
}

Vector Vector::operator/(double d) const {
    return *this * (1 / d);
}

double Vector::operator*(const Vector &rhs) const {
    return x * rhs.x + y * rhs.y;
}

double Vector::operator^(const Vector &rhs) const {
    return x * rhs.y - rhs.x * y;
}

bool Vector::operator==(const Vector &rhs) const {
    return dcmp(x, rhs.x) == 0 && dcmp(y, rhs.y) == 0;
}

bool Vector::operator!=(const Vector &rhs) const {
    return !(rhs == *this);
}

bool Vector::operator<(const Vector &rhs) const {
    if (dcmp(x, rhs.x) != 0) {
        return dcmp(x, rhs.x) < 0;
    } else {
        return dcmp(y, rhs.y) < 0;
    }
}

bool Vector::operator>(const Vector &rhs) const {
    return rhs < *this;
}

bool Vector::operator<=(const Vector &rhs) const {
    return !(rhs < *this);
}

bool Vector::operator>=(const Vector &rhs) const {
    return !(*this < rhs);
}

std::ostream &operator<<(std::ostream &os, const Vector &vector) {
    os << "(" << vector.x << "," << vector.y << ")";
    return os;
}

double Vector::dot(const Vector &rhs) const {
    return *this * rhs;
}

double Vector::cross(const Vector &rhs) const {
    return *this ^ rhs;
}

double Vector::length() const {
    return sqrt(*this * *this);
}

double Vector::length2() const {
    return *this * *this;
}

double Vector::angle() const {
    return atan2(y, x);
}

double Vector::angle(const Vector &rhs) const {
    return acos((*this * rhs) / length() / rhs.length());
}

Vector Vector::rotate(double rad) const {
    // Rotate counter-clockwise
    return Vector(x * cos(rad) - y * sin(rad), x * sin(rad) + y * cos(rad));
}

Vector Vector::rotate90() const {
    return Vector(-y, x);
}

Vector Vector::rotate90R() const {
    return Vector(y, -x);
}

Vector Vector::normal() const {
    double l = length();
    return Vector(-y / l, x / l);
}

double Vector::getDistanceTo(const Point &p) const {
    return sqrt(pow(x - p.x, 2) + pow(y - p.y, 2));
}

bool Vector::cmpByAngle(const Vector &a, const Vector &b) {
    return dcmp(a.angle(), b.angle()) < 0;
}

Vector Vector::truncate(double d) const {
    double l = length();
    if (sign(l) == 0) {
        return *this;
    }
    d /= l;
    return Vector(x * d, y * d);
}

Line::Line(double x1, double y1, double x2, double y2) : a(x1, y1), b(x2, y2) {}

Line::Line(const Point &a, const Point &b) : a(a), b(b) {}

double Line::getDistanceTo(const Point &p) const {
    const Vector &v1 = b - a;
    const Vector &v2 = p - a;
    return fabs(v1 ^ v2 / v1.length());
}

Point Line::getIntersection(const Line &rhs) const {
    if (!intersects(rhs)) {
        return Point();
    }
    Vector u = a - rhs.a;
    Vector v = b - a;
    Vector w = rhs.b - rhs.a;
    double t = (w ^ u) / (v ^ w);
    return a + v * t;
}

Point Line::getProjection(const Point &p) const {
    const Vector &v = b - a;
    return a + v * (v * (p - a) / (v * v));
}

Point Line::getReflection(const Point &p) const {
    return getProjection(p) * 2 - p;
}

bool Line::contains(const Point &p) const {
    Point p1 = a;
    Point p2 = b;
    if (p1 == p) {
        p1 = p1 + (p2 - p1) * 2;
    } else if (p2 == p) {
        p2 = p2 + (p1 - p2) * 2;
    }
    return sign((p2 - p) ^ (p1 - p)) == 0;
}

bool Line::intersects(const Line &rhs) const {
    return sign((a - b) ^ (rhs.a - rhs.b)) != 0;
}

bool Line::parallels(const Line &rhs) const {
    return !intersects(rhs);
}

bool Line::isPerpendicularTo(const Line &rhs) const {
    return sign((b - a) * (rhs.b - rhs.a)) == 0;
}

Polygon::Polygon(const std::vector<Point> &points) : points(points) {}

Point &Polygon::operator[](const int index) {
    return points[index];
}

int Polygon::size() const {
    return points.size();
}

double Polygon::area() const {
    if (points.size() < 3) {
        return 0;
    }
    double sum = points.back() ^points.front();
    for (int i = 0; i < (int) points.size() - 1; i++) {
        sum += points[i] ^ points[i + 1];
    }
    return sum / 2;
}

double Polygon::circumference() const {
    if (points.size() < 3) {
        return 0;
    }
    double sum = (points.back() - points.front()).length();
    for (int i = 0; i < (int) points.size() - 1; i++) {
        sum += (points[i] - points[i + 1]).length();
    }
    return sum;
}

Polygon Polygon::cutByHalfPlane(const Line &line) const {
    // Left side of the line
    Polygon res;
    for (int i = 0; i < points.size(); i++) {
        int d1 = sign((line.b - line.a) ^ (points[i] - line.a));
        int d2 = sign((line.b - line.a) ^ (points[(i + 1) % points.size()] - line.a));
        if (d1 >= 0) {
            res.points.push_back(points[i]);
        }
        if (d1 * d2 < 0) {
            res.points.push_back(line.getIntersection(Line(points[i], points[(i + 1) % points.size()])));
        }
    }
    return res;
}

int main() {
//    freopen("data.in", "r", stdin);

    double x, y;
    double x2, y2;
    int n, q;
    while (~scanf("%d", &n)) {
        vector<Point> points;
        points.reserve(n);
        for (int i = 0; i < n; i++) {
            scanf("%lf%lf", &x, &y);
            points.emplace_back(x, y);
        }
        Polygon polygon(points);

        scanf("%d", &q);
        while (q--) {
            scanf("%lf%lf", &x, &y);
            scanf("%lf%lf", &x2, &y2);

            printf("%.10f\n", polygon.cutByHalfPlane(Line(x, y, x2, y2)).area());
        }
    }
    return 0;
}



Measured memory_bytes: 3240