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Arc length from given Angle
  • Last Updated : 06 Jul, 2018

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;
  
// functuion 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 {
      
    // functuion 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
  
# functuion 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 {
      
    // functuion 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
  
// functuion 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
?>



Output:

9.821428571428571

This article is contributed by Chinmoy Lenka. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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