#include<iostream> using namespace std; int main(){ float a; a=1; cout<<(a*a)*3.1415926<<endl; float b; b=3; cout<<(b*b)*3.1415926<<endl; float c; c=5; cout<<(c*c)*3.1415926<<endl; float d; d=7; cout<<(d*d)*3.1415926<<endl; float e; e=9; cout<<(e*e)*3.1415926<<endl; return 0; }