Program to calculate the area between two Concentric Circles

Given two concentric circles with radius X and Y where (X > Y). Find the area between them.

You are required to find the area of the green region as shown in the following image:

Examples:



Input : X = 2, Y = 1
Output : 9.42478

Input : X = 4, Y = 2
Output : 37.6991

Approach:

The area between the two given concentric circles can be calculated by subtracting the area of the inner circle from the area of the outer circle. Since X>Y. X is the radius of the outer circle.

Therefore, area between the two given concentric circles will be:

π*X2 - π*Y2

Below is the implementation of the above approach:

C++

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// C++ program to find area between the
// two given concentric circles
  
#include <bits/stdc++.h>
using namespace std;
  
// Function to find area between the
// two given concentric circles
double calculateArea(int x, int y)
{
    // Declare value of pi
    double pi = 3.1415926536;
  
    // Calculate area of outer circle
    double arx = pi * x * x;
  
    // Calculate area of inner circle
    double ary = pi * y * y;
  
    // Difference in areas
    return arx - ary;
}
  
// Driver Program
int main()
{
    int x = 2;
    int y = 1;
  
    cout << calculateArea(x, y);
  
    return 0;
}

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Java

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// Java program to find area between the
// two given concentric circles
import java.io.*;
  
class GFG 
{
      
// Function to find area between the
// two given concentric circles
static double calculateArea(int x, int y)
{
    // Declare value of pi
    double pi = 3.1415926536;
  
    // Calculate area of outer circle
    double arx = pi * x * x;
  
    // Calculate area of inner circle
    double ary = pi * y * y;
  
    // Difference in areas
    return arx - ary;
}
  
// Driver code
public static void main (String[] args) 
{
    int x = 2;
    int y = 1;
    System.out.println (calculateArea(x, y));
}
}
  
// This code is contributed by jit_t.

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Python 3

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# Python3 program to find area between  
# the two given concentric circles 
  
# Function to find area between the 
# two given concentric circles 
def calculateArea(x, y): 
  
    # Declare value of pi 
    pi = 3.1415926536
  
    # Calculate area of outer circle 
    arx = pi * x *
  
    # Calculate area of inner circle 
    ary = pi * y *
  
    # Difference in areas 
    return arx - ary 
  
# Driver Code
x = 2
y = 1
  
print(calculateArea(x, y)) 
  
# This code is contributed 
# by shashank_sharma

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C#

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// C# program to find area between the
// two given concentric circles
using System;
  
class GFG 
{
      
// Function to find area between the
// two given concentric circles
static double calculateArea(int x, int y)
{
    // Declare value of pi
    double pi = 3.1415926536;
  
    // Calculate area of outer circle
    double arx = pi * x * x;
  
    // Calculate area of inner circle
    double ary = pi * y * y;
  
    // Difference in areas
    return arx - ary;
}
  
// Driver code
public static void Main () 
{
    int x = 2;
    int y = 1;
    Console.WriteLine(calculateArea(x, y));
}
}
  
// This code is contributed by Code_Mech.

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PHP

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<?php
// PHP program to find area between the
// two given concentric circles
  
// Function to find area between the
// two given concentric circles
function calculateArea($x, $y)
{
    // Declare value of pi
    $pi = 3.1415926536;
  
    // Calculate area of outer circle
    $arx = $pi * $x * $x;
  
    // Calculate area of inner circle
    $ary = $pi * $y * $y;
  
    // Difference in areas
    return ($arx - $ary);
}
  
// Driver Code
$x = 2;
$y = 1;
  
echo calculateArea($x, $y);
  
// This code is contributed by akt_mit
?>

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Output:

9.42478

Time Complexity: O(1)



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