#include <bits/stdc++.h>
#define fir first
#define sec second
#define el '\n'
#define debug(x) cout << #x << ":: " << x << endl;

#define FINISH cout << "FINISH" << endl;

#define debugv(x) cout << #x << ":: ";\
    for (auto i : x)                \
        cout << i << " ";           \
    cout << endl

using namespace std;

using ll = long long;
using ld = long double;
using PII = pair<int, int>;
const int inf = 0x3f3f3f3f;
const int N = 200020;
const ld PI = 3.14159265358979323846;
struct point{
	ll x, y;
	ld ang;
};

ld getang(int x, int y) {
	if (x == 0 || y == 0) {
		if (x > 0 && y == 0) {
			return 0.0;
		}
		else if (x == 0 && y > 0) {
			 return PI / 2;
		}
		else if (x < 0 && y == 0) {
			return PI;
		}
		else {
			return PI * 3 / 2;
		}
	}

	if (y > 0) {
		return atan(y / x);
	}
	else {
		return PI + atan(y / x);
	}
}

void solve()
{
	int n, k;
	cin >> n >> k;
	vector<point> a(2 * n + 1);
	for (int i = 1; i <= n; i++) {
		cin >> a[i].x >> a[i].y;
		a[i].ang = getang(a[i].x, a[i].y);
	}
	for (int i = 1; i <= n; i++) {
		a[i + n].ang = a[i].ang + PI * 2;
	}
	sort(next(a.begin()), a.end(), [&] (point x, point y) {
		return x.ang < y.ang;
	});
	ld ans = 0;
	for (int i = 1; i <= n; i++) {
		ld nxt = a[i + k].ang - a[i].ang;
		ans = max(ans, nxt);
	}
	cout << fixed << setprecision(10) << ans << el;
}

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