C++ : find area and circumference of circle

#include<iostream>
#include<conio.h>
using namespace std;
const float pi=3.1415;
int main()
{
float r,area,circum;
cout<<"Enter the ardius of the circle : ";
cin>>r;
area=pi*r*r;
circum=2*pi*r;
cout<<endl<<endl;
cout<<"Area : "<<area<<endl;
cout<<"Circumference : "<<circum<<endl;
getch()
return(0);
}