#include <bits/stdc++.h>
#define int long long
#define double long double
const double pi = 3.14159265358979;
using namespace  std;

void solve()
{
    int n,k;
    cin >> n >> k;
    vector<double>p;
    double one = 1.0;
    for(int i = 0; i < n; ++ i)
    {
        double x,y;
        cin >> x >> y;
        if(y == 0)
        {
            if(y > 0) p.push_back(0);
            else p.push_back(pi);
            continue;
        }
        if(x == 0)
        {
            if(x > 0) p.push_back(pi/2.);
            else p.push_back(pi*3./2.);
            continue;
        }
        double a = atan(fabs(one * y / x));
        if(x > 0 && y > 0)p.push_back(a);
        if(x > 0 && y < 0)p.push_back(2.*pi-a);
        if(x < 0 && y > 0)p.push_back(pi-a);
        if(x < 0 && y < 0) p.push_back(pi+a);
    }
    sort(p.begin(),p.end());
    double ans = 0.0;
    for(int i = 0; i < n; ++ i)
    {
        if(i + k < n) ans = max(ans, p[i+k] - p[i]);
        else ans = max(ans, p[i+k-n] + 2.*pi-p[i]);
    }
    cout << fixed << setprecision(10) << ans << '\n';
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr), cout.tie(nullptr);
    int _;
    cin >> _;
    while(_--)solve();
}