# Program to calculate the area between two Concentric Circles

• Last Updated : 14 Apr, 2021

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:

`Ï€*X2 - Ï€*Y2`

Below is the implementation of the above approach:

## C++

 `// C++ program to find area between the``// two given concentric circles` `#include ``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;``}`

## Java

 `// 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.`

## Python3

 `# 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 ``*` `x` `    ``# Calculate area of inner circle``    ``ary ``=` `pi ``*` `y ``*` `y` `    ``# Difference in areas``    ``return` `arx ``-` `ary` `# Driver Code``x ``=` `2``y ``=` `1` `print``(calculateArea(x, y))` `# This code is contributed``# by shashank_sharma`

## C#

 `// 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.`

## PHP

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## Javascript

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Output:
`9.42478`

Time Complexity: O(1)

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