Answer:
The correct program to this question can be given as:
Program:
//header file
#include<iostream> //include header file
using namespace std;
//main
int main() //defining method main
{
double radius,area=0; //defining variables
double PI=3.14; //defining variable PI and assign value
cout <<"Enter the radius: "; //message
cin >> radius; //input value by user
area = PI * radius * radius; //formula to calculate area
cout << "Area: "<< area << endl; //print area
return 0;
}
Output:
Enter the radius: 3.0
Area: 28.26
Explanation:
In the above program code, a header file is included. In the next line, the main method is defined, which contain three double type variable that is "radius, area, and PI".
- The radius variable is used to take input by the user, and the area variable is to calculate the area of the circle, and the PI is used to hold a constant value, which is "3.14".
- After taking user input in radius variable the area variable has used the formula of the circle, which calculates a value and in the last print, the function uses "cout", that prints area variable value.
