#include <bits/stdc++.h>
#define For(i, l, r) for (int i=l; i<=r; ++i)
using namespace std;
template <typename T>
inline void read(T &x) {
    char c = getchar(); int w = 1; x = 0;
    while (!isdigit(c))
        (c == '-') && (w = -w), c = getchar();
    while (isdigit(c))
        x = x * 10 + (c ^ '0'), c = getchar();
    x *= w;
}

const double Pi = acos(-1.0);
const int N = 200010;
int T, n, k;
double x, y, a[N];
signed main() {
    read(T);
    while (T -- > 0) {
        read(n); read(k);
        For(i, 1, n) {
            read(x); read(y);
            if (!x) {
                if (y > 0) a[i] = Pi/2.0;
                else a[i] = Pi*3.0/2;
                continue;
            }
            if (!y) {
                if (x < 0) a[i] = Pi;
                else a[i] = 0;
                continue;
            }
            double Ang = atan(y / x);
            if (Ang < 0) Ang += Pi;
            if (y < 0) {
                Ang += Pi;
            }
            a[i] = Ang;
        }
        std :: sort(a + 1, a + n + 1);
        double Ans = 0;
        if (n == k) {
            Ans = 2 * Pi;
        }
        for (int i=1; i<=n; ++i) {
            double Now = a[(i+k-1)%n+1] - a[i];
            if (Now < 0) Now += 2 * Pi;
            Ans = max(Ans, Now);
        }
        printf("%.10lf\n", Ans);
    }
    return 0;
}
/*
5
1 1
0 1

8 2
1 0
1 1
0 1
-1 1
-1 0
-1 -1
0 -1
1 -1

4 2
-1 1
0 1
0 2
1 1

4 2
-1000000000 0
-998244353 1
998244353 1
1000000000 0

3 1
0 1
0 2
0 -1
*/