Question

Calculate the area and perimeter(circumference) of a circle. Print the area and perimeter(circumference) Use a radius of 15 to test your program, calculations should have 2 decimal places. In C++, please use visual studios, and show the output.

Answer 1

#include <iostream>
#include <iomanip>
using namespace std;

#define PI 3.14159

double area(double radius) {
    return PI * radius * radius;
}

double perimeter(double radius) {
    return 2 * PI * radius;
}

int main() {
    double radius;
    cout << "Enter radius: ";
    cin >> radius;
    cout << setprecision(2) << fixed;
    cout << "Radius: " << radius << endl;
    cout << "Area: " << area(radius) << endl;
    cout << "Perimeter: " << perimeter(radius) << endl;
    return 0;
}

Answer 2

Below is a C++ program to calculate the area and circumference (perimeter) of a circle using a given radius of 15. The calculations will be displayed with two decimal places.

cppCopy code#include <iostream>#include <cmath>#include <iomanip>using namespace std;const double PI = 3.14159265359;int main() {    double radius = 15.0;    double area = PI * pow(radius, 2);    double circumference = 2 * PI * radius;

    cout << fixed << setprecision(2);
    cout << "Radius: " << radius << endl;
    cout << "Area: " << area << endl;
    cout << "Circumference (Perimeter): " << circumference << endl;    return 0;
}

Save the above code in a C++ source file (e.g., "main.cpp") and compile and run it using Visual Studio. The program will output the following:

makefileCopy codeRadius: 15.00Area: 706.86Circumference (Perimeter): 94.25

This shows that for a circle with a radius of 15 units, the area is approximately 706.86 square units, and the circumference (perimeter) is approximately 94.25 units, both rounded to two decimal places.