1095

 1 #include <iostream>
 2 #include <iomanip>
 3 using namespace std;
 4 #define p 3.1415
 5 int main()
 6 {
 7     int n;
 8     double s,r;
 9     cin>>n;
10     while(n--)
11     {
12         cin>>r;
13         s=p*r*r;
14     cout<<setiosflags(ios::fixed)<<setprecision(6)<<s<<endl;
15     }
16     return 0;
17 }