#include <bits/stdc++.h> ? using namespace std; int main() { cout<<3.1415926*(1*1)<<endl; cout<<3.1415926*(3*3)<<endl; cout<<3.1415926*(5*5)<<endl; cout<<3.1415926*(7*7)<<endl; cout<<3.1415926*(9*9)<<endl; return 0; }