#include<iostream> using namespace std; int main(){ double C=1,b=3,a=5,s=7,g=9; cout<<C*C*3.1415926<<endl; cout<<b*b*3.1415926<<endl; cout<<a*a*3.1415926<<endl; cout<<s*s*3.1415926<<endl; cout<<g*g*3.1415926<<endl; return 0; }