#include <bits/stdc++.h>
#define int long long
#define endl '\n'

using namespace std;

const int INF = 0x3f3f3f3f3f3f3f3f;
const double PI = acos(-1); // 统一使用`acos(-1)`计算 PI 的值
typedef pair<int, int> PII;

struct Node {
    double degree;
    int count;
};

void init() {
    // 可用于初始化全局变量或执行必要的设置
}

void solve() {
    int n, k;
    cin >> n >> k;

    vector<double> degrees(n + 1);
    vector<Node> aa;

    for (int i = 1; i <= n; i++) {
        int x, y;
        cin >> x >> y;
        degrees[i] = atan2(y, x);
        // if (degrees[i] < 0) {
        //     degrees[i] += 2 * PI; // 改为使用统一的 PI
        // }
    }

    sort(degrees.begin() + 1, degrees.end());

    for (int i = 1; i <= n; i++) {
        if (!aa.empty() && abs(degrees[i] - aa.back().degree) < 1e-9) { // 防止浮点误差
            aa.back().count++;
        } else {
            aa.push_back({degrees[i], 1});
        }
    }

    int m = aa.size();
    vector<int> sum_cnt(2 * m);
    for (int i = 0; i < m; i++) {
        aa.push_back({aa[i].degree + 2 * PI, aa[i].count}); // 将环状角度映射到线性区间
    }

    sum_cnt[0] = aa[0].count;
    for (int i = 1; i < 2 * m; i++) {
        sum_cnt[i] = sum_cnt[i - 1] + aa[i].count;
    }

    double ans = 0;

    // 滑动窗口计算最小角度范围
    auto calc = [&](int i, int j) {
        if (i == 0) {
            return sum_cnt[j] - max(aa[i].count, aa[j].count);
        } else {
            return sum_cnt[j] - sum_cnt[i - 1] - max(aa[i].count, aa[j].count);
        }
    };

    for (int i = 0, j = 0; i < m; i++) {
        j = max(i, j);
        while (j + 1 < aa.size() && calc(i, j) < k) {
            j++;
        }
        if (j < aa.size() && calc(i, j) >= k) {
            ans = max(ans, aa[j].degree - aa[i].degree);
        }
    }

    ans = min(ans, 2 * PI); // 最终角度范围不能超过 2PI
    cout << ans << endl;
}

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

    cout << fixed << setprecision(10);

    int t;
    cin >> t;
    init();

    while (t--) {
        solve();
    }

    return 0;
}