#include<stdio.h>
#include<math.h>
#define pi acos(-1)
main()
{int i,n[20],num;
 float r[20];
 scanf("%d",&num);
 for(i=1;i<=num;i++)
 {scanf("%f%d",&r[i],&n[i]);
 if(r[i]<1||r[i]>100||n[i]<2||n[i]>100){i--;continue;}}
 for(i=1;i<=num;i++)
 {printf("Scenario #%d:\n%.3f\n\n",i,r[i]*sin(pi/n[i])/(1+sin(pi/n[i])));}
}