1799_Yeehaa

gistfile1.txt

#include <iostream>
#include <tgmath.h>

using namespace std;

#define PI 3.14159265
int main()
{
    int N;
    cin >> N;
    double R, r;
    int n;
    cout.precision(3);
    for (int i=0; i<N; i++)
    {
        cin >> R >> n;
        cout << fixed << R/(1 + 1/sin(PI/n));
    }
    return 0;
}