# Sum of internal angles of a Polygon

Given an integer N, the task is to find the sum of interior angles of an N-sided polygon. A plane figure having a minimum of three sides and angles is called a polygon.

Examples:

Input: N = 3
Output: 180
3-sided polygon is a triangle and the sum
of the interior angles of a triangle is 180.

Input: N = 6
Output: 720

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The sum of internal angles of a polygon with N sides is given by (N – 2) * 180

Below is the implementation of the above approach:

 `// C++ implementation of the approach ` `#include ` `using` `namespace` `std; ` ` `  `// Function to return the sum of internal ` `// angles of an n-sided polygon ` `int` `sumOfInternalAngles(``int` `n) ` `{ ` `    ``if` `(n < 3) ` `        ``return` `0; ` `    ``return` `(n - 2) * 180; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `n = 5; ` ` `  `    ``cout << sumOfInternalAngles(n); ` ` `  `    ``return` `0; ` `} `

 `// Java implementation of the approach ` `class` `GFG { ` ` `  `    ``// Function to return the sum of internal ` `    ``// angles of an n-sided polygon ` `    ``static` `int` `sumOfInternalAngles(``int` `n) ` `    ``{ ` `        ``if` `(n < ``3``) ` `            ``return` `0``; ` `        ``return` `((n - ``2``) * ``180``); ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `        ``int` `n = ``5``; ` ` `  `        ``System.out.print(sumOfInternalAngles(n)); ` `    ``} ` `} `

 `// C# implementation of the approach ` `using` `System; ` `class` `GFG { ` ` `  `    ``// Function to return the sum of internal ` `    ``// angles of an n-sided polygon ` `    ``static` `int` `sumOfInternalAngles(``int` `n) ` `    ``{ ` `        ``if` `(n < 3) ` `            ``return` `0; ` `        ``return` `((n - 2) * 180); ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 5; ` ` `  `        ``Console.Write(sumOfInternalAngles(n)); ` `    ``} ` `} `

 `# Python3 implementation of the approach ` ` `  `# Function to return the sum of internal  ` `# angles of an n-sided polygon ` `def` `sumOfInternalAngles(n): ` `    ``if``(n < ``3``): ` `        ``return` `0` `    ``return` `((n ``-` `2``) ``*` `180``) ` ` `  `# Driver code ` `n ``=` `5` `print``(sumOfInternalAngles(n)) `

 ` `

Output:
```540
```

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