Poj Solution 1799

http://poj.org/problem?id=1799

//* @author popop0p0popo
import java.util.*;
import java.io.*;
import java.text.*;

public class Main{
 public static void main(String[] args){
    Scanner scanner=new Scanner(new BufferedReader(new InputStreamReader(System.in)));
    int n=scanner.nextInt();
    double r,t;
    for (int i=0;i< n ;i++ ){
        r=scanner.nextDouble();
        t=scanner.nextDouble();
        System.out.println("Scenario #"+(i+1)+":");
        DecimalFormat df=new DecimalFormat("0.000");
        System.out.println(df.format(r*(1.0-1.0/(1.0+Math.sin(Math.PI/t)))));
        System.out.println();
    }
 }
}