#include<bits/stdc++.h> using namespace std; const double eps = 1e-9; //浮点数精度控制 #define Vector point #define Point point const double PI = acos(-1); struct Point{ double x,y; Point(double x=0,double y=0) :x(x),y(y){} friend Vector operator + (Vector A,Vector B){ return Vector(A.x + B.x , A.y + B.y);} friend Vector operator - (Point A,Point B){ return Vector(A.x - B.x , A.y - B.y);} friend Vector operator * (Vector A,double p) {return Vector(A.x*p , A.y*p);} friend Vector operator / (Vector A,double p) {return Vector(A.x/p,A.y/p);} friend bool operator < (const Point &a,const Point &b){ return a.x< b.x || ( a.x == b.x && a.y < b.y); } }; int dcmp(double k){ return k < -eps ?-1:k>eps?1:0; } double sqr(double k){return k*k;} double mysqrt(double n){ return sqrt(max(0.0,n));} double cross(Vector A,Vector B){return A.x*B.y - A.y*B.x;} double dot(Vector A,Vector B){return A.x*B.x + A.y*B.y;} double abs(Point o){return sqrt(dot(o,o));} point _a[205],o; int P,Q; int n; double r; double ALL; void circle_cross_line(Point a,Point b,Point o,double r,Point ret[],int &num){ double x0 = o.x,y0 = o.y; double x1 = a.x,y1 = a.y; double x2 = b.x,y2 = b.y; double dx = x2 - x1,dy = y2-y1; double A = dx*dx +dy*dy; double B = 2*dx*(x1-x0)+2*dy*(y1-y0); double C = sqr(x1-x0)+sqr(y1-y0)-sqr(r); double delta = B*B - 4*A*C; num = 0; if(dcmp(delta)>=0){ double t1 = (-B-mysqrt(delta))/(2*A); double t2 = (-B+mysqrt(delta))/(2*A); if(dcmp(t1-1)<=0 && dcmp(t1)>=0){ ret[num++] = Point(x1+t1*dx , y1 + t1*dy); } if(dcmp(t2-1)<=0 && dcmp(t2)>=0){ ret[num++] = Point(x1 + t2*dx,y1+t2*dy); } } } double sector_area(point a,point b){ double theta = atan2(a.y,a.x) - atan2(b.y,b.x); while(theta <=0) theta+=2*PI; while(theta > 2*PI) theta -= 2*PI; theta = min (theta,2*PI - theta); return r*r *theta / 2; } double calc(Point a,Point b){ Point p[2]; int num = 0; int ina = dcmp(abs(a)-r)<0; int inb = dcmp(abs(b)-r)<0; if(ina){ if(inb){ return fabs(cross(a,b))/2.0; }else{ circle_cross_line(a,b,Point(0,0),r,p,num); return sector_area(b,p[0])+fabs(cross(a,p[0]))/2.0; } }else{ if(inb) { circle_cross_line(a,b,Point(0,0),r,p,num); return sector_area(p[0],a)+fabs(cross(p[0],b))/2.0; }else{ circle_cross_line(a,b,Point(0,0),r,p,num); if(num == 2){ return sector_area(a,p[0]) + sector_area(p[1],b) + fabs(cross(p[0],p[1]))/2.0; }else { return sector_area(a,b); } } } } double area(){ double ret = 0; for(int i = 1;i<=n;i++){ int sgn = dcmp(cross(_a[i],_a[i+1])); if(sgn!=0) ret+=sgn * calc(_a[i],_a[i+1]); } return abs(ret); } bool check() { double are = area(); if(dcmp(are - ALL)<0) return false; return true; } Point __a[206]; double PolygonArea(){ double area = 0; for(int i = 2;i<n;i++) { area+=cross(__a[i] - __a[1],__a[i+1] - __a[1]); } return fabs(area*0.5); } int main() { cin>>n; for(int i = 1;i<=n;i++) cin>>__a[i].x>>__a[i].y; __a[n+1] = __a[1]; n++; int m;cin>>m; double all = PolygonArea(); while(m--) { cin>>o.x>>o.y>>P>>Q; for(int i = 1;i<=n;i++) _a[i] = __a[i] - o; P = Q-P; ALL = P*all/Q; double L = 0,R = 5000000; while(dcmp(L-R)!=0) { r =(L+R)/2.0; if(check()) R = r; else L = r; } printf("%.10f\n",L); } }