1799

/*
简单的数学几何题
*/// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>using namespace std;// typedef
typedef __int64 LL;// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)#define Z(a,b) ((a)<<(b))
#define Y(a,b) ((a)>>(b))const double eps = 1e-6;
const double INFf = 1e100;
const int INFi = 1000000000;
const LL INFll = (LL)1<<62;
const double Pi = acos(-1.0);template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{if(x>y) return x;return y;
}
template<class T> inline T TMIN(T x,T y)
{if(x<y) return x;return y;
}
template<class T> inline T MMAX(T x,T y,T z)
{return TMAX(TMAX(x,y),z);
}
template<class T> inline T MMIN(T x,T y,T z)
{return TMIN(TMIN(x,y),z);
}
template<class T> inline void SWAP(T &x,T &y)
{T t = x;x = y;y = t;
}// code begin
int T, N;
double R,a,r;
int main()
{read;write;scanf("%d",&T);for(int i=1;i<=T;i++){scanf("%lf %d",&R,&N);a = (2*Pi)/N;a = sin(a/2);printf("Scenario #%d:\n",i);printf("%.3f\n\n",R*a/(1+a) );}return 0;
}