Question

Составить программу вычисления площади круга

Answer 1

Program prog;
uses crt;
var
  s,r: real;
begin
  Write('Радиус круга  =  ');
  readln(r);

  s:=pi*sqr(r);
  writeln('S = ',s:0:3);
 
end.

Answer 2

Program to Calculate the Area of a Circle

To calculate the area of a circle, you can use the formula A = πr^2, where A is the area and r is the radius of the circle. Here's an example program in C++ that calculates the area of a circle:

#include 
using namespace std;

int main() {
    const double pi = 3.14;
    double radius;

cout << "Enter the radius of the circle: ";
    cin >> radius;

double area = pi * radius * radius;

cout << "The area of the circle is: " << area << endl;

return 0;
}

In this program, we first declare a constant variable `pi` and assign it the value of 3.14, which is an approximation of the mathematical constant π. We then declare a variable `radius` to store the user input for the radius of the circle.

The program prompts the user to enter the radius of the circle using the `cout` statement and reads the input using the `cin` statement.

Next, we calculate the area of the circle using the formula `area = pi * radius * radius` and store the result in the variable `area`.

Finally, we display the calculated area using the `cout` statement.

You can run this program and enter the radius of the circle to get the corresponding area.

Note: This program assumes that the radius entered by the user is a valid numeric value. It does not handle input validation or error checking.