# Arc length from given Angle

An angle is a geometrical figure when two rays meet at a common point on a plane. These rays form the sides of the angle and the meeting point is referred as the vertex of the angle. There is something that we need to keep in mind that the plane that forms an angle doesn’t need to be a Euclidean plane. Now, in a circle, the length of an arc is a portion of the circumference. The figure explains the various parts we have discussed:

Given an angle and the diameter of a circle, we can calculate the length of the arc using the formula:

ArcLength = ( 2 * pi * radius ) * ( angle / 360 ) Where pi = 22/7, diameter = 2 * radius, angle is in degree.

**Examples : **

Input : Diameter = 25 Angle = 45 Explanation : ((22/7) * 25) * (45/360) Output : 9.821 (rounded) Input : Diameter = 80 Angle = 60 Explanation : ((22/7) * 80) * (60/360) Output : 41.905 (rounded)

**Note: **If angle is greater than or equal to 360 degree, then the arc length cannot be calculated, since no angle is possible.

## C++

`// C++ program to calculate` `// length of an arc` `#include <iostream>` `using` `namespace` `std;` `// function to calculate ` `// arc length` `double` `arcLength(` `double` `diameter, ` ` ` `double` `angle)` `{` ` ` `double` `pi = 22.0 / 7.0;` ` ` `double` `arc;` ` ` `if` `(angle >= 360) ` ` ` `{` ` ` `cout<< ` `"Angle cannot"` `,` ` ` `" be formed"` `;` ` ` `return` `0;` ` ` `}` ` ` `else` ` ` `{` ` ` `arc = (pi * diameter) * ` ` ` `(angle / 360.0);` ` ` `return` `arc;` ` ` `}` `}` `// Driver Code` `int` `main() ` `{` ` ` `double` `diameter = 25.0;` ` ` `double` `angle = 45.0;` ` ` ` ` `double` `arc_len = arcLength(diameter, ` ` ` `angle);` ` ` `cout << (arc_len);` ` ` `return` `0;` `}` |

## Java

`// Java program to calculate ` `// length of an arc` `public` `class` `Arc {` ` ` ` ` `// function to calculate arc length` ` ` `static` `double` `arcLength(` `double` `diameter, ` ` ` `double` `angle)` ` ` `{` ` ` `double` `pi = ` `22.0` `/ ` `7.0` `;` ` ` `double` `arc;` ` ` `if` `(angle >= ` `360` `) {` ` ` `System.out.println(` `"Angle cannot"` ` ` `+ ` `" be formed"` `);` ` ` `return` `0` `;` ` ` `}` ` ` `else` `{` ` ` `arc = (pi * diameter) * (angle / ` `360.0` `);` ` ` `return` `arc;` ` ` `}` ` ` `}` ` ` ` ` `// Driver Code` ` ` `public` `static` `void` `main(String args[])` ` ` `{` ` ` `double` `diameter = ` `25.0` `;` ` ` `double` `angle = ` `45.0` `;` ` ` `double` `arc_len = arcLength(diameter, angle);` ` ` `System.out.println(arc_len);` ` ` `}` `}` |

## Python3

`# Python3 code to calculate ` `# length of an arc` `import` `math` `# function to calculate arc length` `def` `arcLength(diameter, angle ):` ` ` `if` `angle >` `=` `360` `:` ` ` `print` `(` `"Angle cannot be formed"` `)` ` ` `return` `0` ` ` `else` `:` ` ` `arc ` `=` `(` `3.142857142857143` `*` `diameter) ` `*` `(angle ` `/` `360.0` `)` ` ` `return` `arc` ` ` `# Driver Code` `diameter ` `=` `25.0` `angle ` `=` `45.0` `arc_len ` `=` `arcLength(diameter, angle)` `print` `(arc_len)` `# This code is contributed by "Sharad_Bhardwaj".` |

## C#

`// C# program to calculate length of an arc` `using` `System;` `public` `class` `GFG {` ` ` ` ` `// function to calculate arc length` ` ` `static` `double` `arcLength(` `double` `diameter, ` ` ` `double` `angle)` ` ` `{` ` ` `double` `pi = 22.0 / 7.0;` ` ` `double` `arc;` ` ` `if` `(angle >= 360) {` ` ` `Console.WriteLine(` `"Angle cannot"` ` ` `+ ` `" be formed"` `);` ` ` `return` `0;` ` ` `}` ` ` `else` `{` ` ` `arc = (pi * diameter) * (angle / 360.0);` ` ` `return` `arc;` ` ` `}` ` ` `}` ` ` ` ` `// Driver Code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` ` ` `double` `diameter = 25.0;` ` ` `double` `angle = 45.0;` ` ` ` ` `double` `arc_len = arcLength(diameter, angle);` ` ` ` ` `Console.WriteLine(arc_len);` ` ` `}` `}` `// This code is contributed by Anant Agarwal.` |

## PHP

`<?php` `// PHP program to calculate ` `// length of an arc` `// function to calculate ` `// arc length` `function` `arcLength(` `$diameter` `, ` ` ` `$angle` `)` ` ` `{` ` ` `$pi` `= 22.0 / 7.0;` ` ` `$arc` `;` ` ` `if` `(` `$angle` `>= 360) ` ` ` `{` ` ` `echo` `"Angle cannot"` `,` ` ` `" be formed"` `;` ` ` `return` `0;` ` ` `}` ` ` `else` ` ` `{` ` ` `$arc` `= (` `$pi` `* ` `$diameter` `) * ` ` ` `(` `$angle` `/ 360.0);` ` ` `return` `$arc` `;` ` ` `}` ` ` `}` ` ` `// Driver Code` `$diameter` `= 25.0;` `$angle` `= 45.0;` `$arc_len` `= arcLength(` `$diameter` `, ` `$angle` `);` `echo` `(` `$arc_len` `);` `// This code is contributed by ajit` `?>` |

## Javascript

`<script>` `// JavaScript program to calculate ` `// length of an arc ` `// function to calculate ` `// arc length ` `function` `arcLength(diameter, angle) ` `{ ` ` ` `let pi = 22.0 / 7.0; ` ` ` `let arc; ` ` ` `if` `(angle >= 360) ` ` ` `{ ` ` ` `document.write(` `"Angle cannot"` `+ ` ` ` `" be formed"` `); ` ` ` `return` `0; ` ` ` `} ` ` ` `else` ` ` `{ ` ` ` `arc = (pi * diameter) * ` ` ` `(angle / 360.0); ` ` ` `return` `arc; ` ` ` `} ` `} ` `// Driver Code ` ` ` `let diameter = 25.0; ` ` ` `let angle = 45.0; ` ` ` ` ` `let arc_len = arcLength(diameter, ` ` ` `angle); ` ` ` `document.write(arc_len); ` `// This code is contributed by Surbhi Tyagi.` `</script>` |

**Output:**

9.821428571428571

**Time Complexity:** O(1)**Auxiliary Space:** O(1)

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