#include <bits/stdc++.h>
using i64 = long long;

std::mt19937 rnd(std::chrono::steady_clock::now().time_since_epoch().count());
constexpr i64 inf = 1e13;
constexpr auto operator"" _f(const char* str, std::size_t len) {
    return [fmt = std::string_view(str, len)](auto&&... args) {
        return std::vformat(fmt, std::make_format_args(args...));
    };
}
const double PI = std::acos(-1);
void solve() {
    int n, k;
    std::cin >> n >> k;

    std::vector<long double> a(n);
    for (int i = 0, x, y;i < n;i ++) {
        std::cin >> x >> y;
        a[i] = std::atan2(y, x);
    }
    std::ranges::sort(a);
    for (int i = 0;i < n;i ++) a.push_back(a[i] + 2 * PI);

    long double max = 0;
    for (int i = 0;i < n;i ++) {
        max = std::max(max, a[i + k] - a[i]);
    }
    std::cout << std::fixed << std::setprecision(7) << max << "\n";
}
signed main() {
    std::cin.tie(nullptr)->sync_with_stdio(false);
    int _ = 1;
    std::cin >> _;
    while (_ --) {
        solve();
    }
    return 0;
}