#include<bits/stdc++.h>
#define int long long
#define db long double
using namespace std;
int n, k;
const db pi = 3.1415927;
void solve() {
    cin >> n >> k;
    vector<db> aa;
    db one = 1.0;
    for(int i = 1, x, y; i <= n; i ++) {
        cin >> x >> y;
        if(y == 0) {
            if(x > 0)
                aa.push_back(0);
            else
                aa.push_back(pi);
        } else if(x == 0) {
            if(y > 0) {
                aa.push_back(pi / 2);
            } else {
                aa.push_back(pi * 3 / 2);
            }
        } else {
            if(x < 0 && y < 0) aa.push_back(atan(one * y/x) + pi);
            else if(x < 0 && y > 0) aa.push_back(atan(one * y/x) + pi);
            else if(x > 0 && y < 0) aa.push_back(atan(one * y / x) + pi * 2);
            else aa.push_back(atan(one * y / x));
        }
    }
    db ans = 0;
    sort(aa.begin(), aa.end());
    for(int i = 0; i < n; i ++) {
        int h = i + k;
        if(h < n) {
            ans = max(ans, aa[h] - aa[i]);
        } else {
            ans = max(ans, aa[h % n] - aa[i] + 2 * pi);
        }
    }
    cout << fixed << setprecision(10) << ans << '\n';
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    int _ = 1;
    cin >> _;
    while(_ --) solve();
    return 0;
}