#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
#define int long long
using i64 = long long;
struct Point {
    i64 x;
    i64 y;
    Point(i64 x = 0, i64 y = 0) : x(x), y(y) {}
};

bool operator==(const Point &a, const Point &b) {
    return a.x == b.x && a.y == b.y;
}

Point operator+(const Point &a, const Point &b) {
    return Point(a.x + b.x, a.y + b.y);
}

Point operator-(const Point &a, const Point &b) {
    return Point(a.x - b.x, a.y - b.y);
}
ld len(const Point &a) {
    return sqrtl(a.x * a.x + a.y * a.y);
}
//cos
i64 dot(const Point &a, const Point &b) {
    return a.x * b.x + a.y * b.y;
}
//sin
i64 cross(const Point &a, const Point &b) {
    return a.x * b.y - a.y * b.x;
}


void g(ld &a) {
    a = max(a, ld(-0.999999999999999));
    a = min(a, ld(0.999999999999999));
}
const ld PI = 3.1415926536;
ld get(Point a, Point b) {
    int dt = dot(a, b);
    int cro = cross(a, b);
    ld le = len(a) * len(b);
    ld ddt = 1.0 * dt / le;
    ld dcro = 1.0 * cro / le;
    g(ddt);
    g(dcro);
    if(cro > 0) {
        return acos(ddt);
    } else if(cro < 0) {
        return 2.0 * PI - acos(ddt);
    } else {
        if(dt > 0) return 0;
        return PI;
    }
    return 0;
}
Point O = {0, 0};
bool cmp1(Point a, Point b)
{
    return get(O, a) < get(O, b);
}

void solve() {
    int n, k;
    cin >> n >> k;
    vector<Point> a(n);
    for(int i = 0; i < n; i++) {
        cin >> a[i].x >> a[i].y;
        int G = gcd(a[i].x, a[i].y);
        a[i].x /= G;
        a[i].y /= G;
    }
    set<pair<int, int>> st;
    sort(a.begin(), a.end(), cmp1);
    vector<Point> b(2 * n);
    for(int i = 0; i < n; i++) {
        b[i] = b[i + n] = a[i];
    }
    ld ans = 0;
    for(int i = 0; i < n; i++) {
        int j = i + k;
        if(b[i] == b[j]) {
            if(j % n <= i % n) ans = fmax(ans, 2 * PI);
        }
        ans = fmax(ans, get(b[i], b[j]));
    }
    cout << ans << "\n";
}           
    
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cout << fixed << setprecision(10);
    int T = 1;
    cin >> T;
    while(T--) solve();

    return 0;
}