poj1799
简单题
View Code
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;
int main()
{
//freopen("D:\\t.txt", "r", stdin);
int t;
scanf("%d", &t);
for (int i = 0; i < t; i++)
{
double r;
int n;
scanf("%lf%d", &r, &n);
printf("Scenario #%d:\n%.3f\n\n", i + 1, (1 - 1 / (1 + sin(3.1415926 / n))) * r);
}
return 0;
}