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

#define ld long double
#define ll long long

struct Point {
    ld x, y, ang;
    Point() {};
    Point(ld x, ld y): x(x), y(y), ang(atan2(y, x)) {};
    bool operator<(Point p) {
        return ang < p.ang;
    }
};

int main() {
#ifdef TEST
    freopen("zz.in", "r+", stdin);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cout << setprecision(18);
    
    ld PI = M_PI;
    
    int t; cin >> t;
    while (t --) {
        int n, k; cin >> n >> k;
        vector<Point> pts;
        for (int i = 0; i < n; ++ i) {
            int x, y; cin >> x >> y;
            pts.emplace_back(Point(x, y));

        }
        sort(pts.begin(), pts.end());
        for (int i = 1; i <= 2; ++ i) {
            for (int j = 0; j < n; ++ j) {
                Point p = pts[j];
                p.ang += i * 2 * PI;
                pts.emplace_back(p);
            }
        }
        ld res = 0;
        for (int i = 0; i < n; ++ i) res = max(res, pts[i+k].ang - pts[i].ang);
        cout << res << '\n';
    }
}