Given an integer **a** as the side of the square ABCD. The task is to find the area of the leaf AECFA inside the square as shown below:

**Examples:**

Input:a = 7Output:28

Input:a = 21Output:252

**Approach:** To calculate the area of the leaf, first find the area of the half leaf AECA, which can be given as:

Area of half leaf = Area of quadrant AECDA – Area of right triangle ACD.

Thus,Area of half leaf = ( PI * a * a / 4 ) – a * a / 2wherePI = 22 / 7andais the side of the square.

Hence, the area of full leaf will be( PI * a * a / 2 ) – a * a

On takinga * acommon we get,Area of leaf = a * a ( PI / 2 – 1 )

Below is the implementation of the above approach:

## C

`// C program to find the area of` `// leaf inside a square` `#include <stdio.h>` `#define PI 3.14159265` ` ` `// Function to find area of` `// leaf` `float` `area_leaf(` `float` `a)` `{` ` ` `return` `(a * a * (PI / 2 - 1));` `}` ` ` `// Driver code` `int` `main()` `{` ` ` `float` `a = 7;` ` ` `printf` `(` `"%f"` `,` ` ` `area_leaf(a));` ` ` `return` `0;` `}` |

## Java

`// Java code to find the area of` `// leaf inside a square` `import` `java.lang.*;` ` ` `class` `GFG {` ` ` ` ` `static` `double` `PI = ` `3.14159265` `;` ` ` ` ` `// Function to find the area of` ` ` `// leaf` ` ` `public` `static` `double` `area_leaf(` `double` `a)` ` ` `{` ` ` `return` `(a * a * (PI / ` `2` `- ` `1` `));` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `double` `a = ` `7` `;` ` ` `System.out.println(area_leaf(a));` ` ` `}` `}` |

## Python3

`# Python3 code to find the area of leaf ` `# inside a square` `PI ` `=` `3.14159265` ` ` `# Function to find the area of ` `# leaf` `def` `area_leaf( a ):` ` ` `return` `( a ` `*` `a ` `*` `( PI ` `/` `2` `-` `1` `) )` ` ` `# Driver code` `a ` `=` `7` `print` `(area_leaf( a ))` |

## C#

`// C# code to find the area of` `// leaf` `// inside square` `using` `System;` ` ` `class` `GFG {` ` ` `static` `double` `PI = 3.14159265;` ` ` ` ` `// Function to find the area of` ` ` `// leaf` ` ` `public` `static` `double` `area_leaf(` `double` `a)` ` ` `{` ` ` `return` `(a * a * (PI / 2 - 1));` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `double` `a = 7;` ` ` `Console.Write(area_leaf(a));` ` ` `}` `}` |

## PHP

`<?php` `// PHP program to find the ` `// area of leaf` `// inside a square` `$PI` `= 3.14159265;` ` ` `// Function to find area of ` `// leaf` `function` `area_leaf( ` `$a` `)` `{` ` ` `global` `$PI` `;` ` ` `return` `( ` `$a` `* ` `$a` `* ( ` `$PI` `/ 2 - 1 ) );` `}` ` ` `// Driver code` `$a` `= 7;` ` ` `echo` `(area_leaf( ` `$a` `));` `?>` |

**Output:**

28

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