Circle & Cubic Challenge

/************************Circle Challange*******************/

#include <iostream>
#include <math.h>
#include <stdio.h>

using namespace std;

int main()
{
    cout << "Circle Calculator" << endl;
    double radius;
    double diameter,area,circumference;
    double Pi = 3.14;


    cout << "Enter Radius: "; // Type a Radius and press enter
    cin >> radius;
    diameter = 2 * radius;
    cout << "\nDiameter: "<< diameter;
    circumference = diameter * Pi;
    cout << "\nCircumference: "<< circumference;
    area = Pi * pow(radius,2.0);
    cout << "\nArea: "<< area;
    cout << "\n\nBye!";

    return 0;
}
/************************Cubic Challange*******************/
#include <iostream>
#include <math.h>
#include <stdio.h>

using namespace std;

int main()
{
    cout << "Cubic Calculator:" << endl;
    double length;
    double volume,area,circumference;


    cout << "\n\nEnter the side length of the cubic: "; // Type a Radius and press enter
    cin >> length;
    circumference = 12 * length;
    cout << "\nCircumference: "<< circumference;
    area = 6 * pow (length, 2.0);
    cout << "\nArea: "<< area;
    volume = pow (length, 3.0);
    cout << "\nVolume: "<< volume;
    cout << "\n\n\nSee you later!";

    return 0;
}