#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ cout<<1*3.1415926<<endl<<9*3.1415926<<endl<<25*3.1415926<<endl<<49*3.1415926<<endl<<81*3.1415926; }