# include<iostream> using namespace std; int main(){ cout<<1.0*1.0/2*3.1415926<<endl<<3.0*3.0/2*3.1415926<<endl<<5.0*5.0/2*3.1415926<<endl<<7.0*7.0/2*3.1415926<<endl<<9.0*9.0/2*3.1415926; return 0; }