Light OJ 1072

#include<stdio.h>
#include<math.h>
int main()
{
    int t,i,c;
    double R,n,x,r,pi;
    pi=2*acos(0.0);
    scanf("%d",&t);
    for(i=1;i<=t;i++){
        scanf("%lf %lf",&R,&n);
        x=sin(pi/n);
        r=(R*x)/(1+x);
        c=ceil(r);
        if(r==c)
            printf("Case %d: %d\n",i,c);
        else
            printf("Case %d: %lf\n",i,r);
    }
    return 0;
}