#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
using i128 = __int128_t;

bool Memory_begin;

bool Memory_end;

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cerr << (&Memory_end - &Memory_begin) / 1048576.0 << "MB" << '\n';

    int t;
    cin >> t;
    while (t--)
    {
        int n, k;
        cin >> n >> k;
        vector<long double> a(n);
        for (int i = 0, x, y; i < n; i++)
        {
            cin >> x >> y;
            a[i] = atan2((long double)y, (long double)x);
        }
        if (n == k)
        {
            cout << fixed << setprecision(10) << acosl(-1) * 2 << '\n';
            continue;
        }
        sort(a.begin(), a.end());
        for (int i = 0; i < n; i++)
            a.push_back(a[i]);
        long double pi = acosl(-1), ans1 = 0;
        for (int i = 0; i < n; i++)
        {
            long double cur = a[i + k] - a[i];
            if (cur < 0)
                cur += pi * 2;
            ans1 = max(ans1, cur);
        }
        if (fabs(ans1) <= 1e-7)
            ans1 = pi * 2;
        cout << fixed << setprecision(10) << ans1 << '\n';
    }
}
/*
 */