几何专题

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<cstring>
 4 #include<cstdlib>
 5 #include<math.h>
 6 double   PI = acos(-1.0);
 7 using namespace std;
 8 
 9 int main()
10 {
11     int T,n,t;
12     double R,r;
13     scanf("%d",&T);
14     for(t=1;t<=T;t++)
15     {
16         scanf("%lf%d",&R,&n);
17         r = R*sin(PI/n)/(1+sin(PI/n));
18         printf("Scenario #%d:\n",t);
19         printf("%.3lf\n\n",r);
20     }
21     return 0;
22 }