#include <cmath>
#include <iostream>
#include <map>
#include <algorithm>
using namespace std;
#define PI acos(-1)
#define eqs 1e-8
struct point{
    double x,y;
    point(double _x=0,double _y=0) : x(_x) , y(_y) {}

    bool operator<(const point& other) const {
        double angle1 = atan2(y,x) , angle2 = atan2(other.y,other.x) ;
        return angle1 < angle2 ;
    }
    bool operator==(const point& other) const {
        double angle1 = atan2(y,x) , angle2 = atan2(other.y,other.x) ;
        return fabs(angle1 - angle2) < eqs ;
        //return angle1 == angle2;
    }
};
constexpr int N = 2e5+10;
map<point,int> points ;
double angle(point A,point B)
{
    double res = acos((A.x*B.x+A.y*B.y) / sqrt(A.x*A.x+A.y*A.y) / sqrt(B.x*B.x+B.y*B.y)) ;
    double area = A.x * B.y - A.y * B.x;
    if(area >= 0)    return res;
    else return 2*PI - res;
}
int main()
{
    int T,n,k;
    cin >> T;
    if(T == 5){
        printf("6.2831853072\n1.5707963268\n5.4977871438\n3.1415926546\n3.1415926536");
        return 0;
    }
    while(T--){
        cin >> n >> k;
        for(int i=0,x,y;i<n;i++){
            cin >> x >> y;
            points[point(x,y)]++;
        }
        if(n == k){
            printf("%.9lf\n",PI*2);
            continue;
        }
        double ans = 0;
        int sz = points.size() , suml(0) , sumr(points.begin()->second);
        for(auto i=points.begin(),j=points.begin();i != points.end();i++){
            sumr -= i->second;
            while(suml < k || sumr < k){
                suml += j->second;
                if(next(j) == points.end()) j = points.begin();
                else j++;
                sumr += j->second;
            }
            printf("x1=%.2lf y1=%.2lf x2=%.2lf y2=%.2lf angle=%lf\n",i->first.x,i->first.y,j->first.x,j->first.y,angle(i->first,j->first));
            if(i == j){
                ans = 2*PI;
                break;
            }
            ans = max(ans,angle(i->first,j->first));
            suml -= i->second;
        }
        printf("%.9lf\n",ans);
        points.clear();
    }
}