Area of a Circular Sector

A circular sector or circle sector is the portion of a disk enclosed by two radii and an arc, where the smaller area is known as the minor sector and the larger being the major sector. Let’s look at this figure and try to figure out the sector: 

source: Wikipedia ( https://goo.gl/mWijn2 )

In this figure the green shaded part is a sector, “r” is the Radius and “theta” is the angle as shown. Here, we can say that the shaded portion is the minor sector and the other portion is the major sector. “L” is the Arc of the Sector. For more, visit Sector. 
Now let’s see the formula using which the sector of a circle can be calculated. 

The area of the sector is similar to the calculation of the area of the circle, just multiply the area of the circle with the angle of the sector. 
Examples: 

Input:
radius = 9
angle = 60
Explanation:
Sector = ( pi * 9*9 ) * ( 60 / 360 )
Output: 42.42857142857142

Input:
radius = 20
angle = 145
Explanation:
Sector = ( pi * 20*20 ) * ( 145 / 360 )
Output: 506.3492063492063

C++

// C++ program to find Area of a Sector
#include <iostream>
using namespace std;

void SectorArea(double radius,double angle)
{
    if(angle >= 360)
        cout<<"Angle not possible";

    // Calculating area of the sector
    else
    {
        double sector = ((22 * radius * radius) / 7)
                       * (angle / 360);
        cout<<sector;
    }
}

// Driver code
int main()
{
    double radius = 9;
    double angle = 60;
    SectorArea(radius, angle);
    return 0;
}

// This code is contributed by Anant Agarwal.

Java

// Java program to find Area of a Sector

class GFG
{
    static void SectorArea(double radius,double angle)
    {
        if(angle >= 360)
            System.out.println("Angle not possible");

        // Calculating area of the sector
        else
        {
            double sector =((22 * radius * radius) / 7)
                           * (angle / 360);
            System.out.println(sector);
        }
    }

    // Driver code
    public static void main (String[] args)
    {
        double radius = 9;
        double angle = 60;
        SectorArea(radius, angle);
    }
}
// This code is contributed by Anant Agarwal.

Python3

# Python program to find Area of a Sector

def SectorArea(radius, angle):
    pi = 22 / 7

    # Constraint or Limit
    if angle >= 360:
        print("Angle not possible")
        return

    # Calculating area of the sector
    else:
        sector = (pi * radius ** 2) * (angle / 360)
        print(sector)
        return

# Driver code
radius = 9
angle = 60
SectorArea(radius, angle)

C#

// C# program to find Area of a Sector
using System;

class GFG {

    static void SectorArea(double radius, double angle)
    {

        if (angle >= 360)
            Console.WriteLine("Angle not possible");

        // Calculating area of the sector
        else {
            double sector = ((22 * radius * radius) / 7)
                            * (angle / 360);

            Console.WriteLine(sector);
        }
    }

    // Driver code
    public static void Main()
    {
        double radius = 9;
        double angle = 60;

        SectorArea(radius, angle);
    }
}

// This code is contributed by vt_m.

PHP

<?php
// PHP program to find Area of a Sector

function SectorArea( $radius, $angle)
{
    if($angle >= 360)
        echo("Angle not possible");

    // Calculating area of the sector
    else
    {
        $sector = ((22 * $radius * $radius)
                     / 7) * ($angle / 360);
        echo($sector);
    }
}

// Driver code

    $radius = 9;
    $angle = 60;
    SectorArea($radius, $angle);

// This code is contributed by vt_m.
?>

Javascript

<script>

// Javascript program to find Area of a Sector

    function SectorArea(radius, angle)
    {
        if(angle >= 360)
            document.write("Angle not possible");

        // Calculating area of the sector
        else
        {
            let sector =((22 * radius * radius) / 7)
                           * (angle / 360);
            document.write(sector);
        }
    }

// Driver code
        let radius = 9;
        let angle = 60;
        SectorArea(radius, angle);

  // This code is contributed by code_hunt.
</script>

Output: 

42.42857142857142

Time complexity: O(1)
Auxiliary Space: O(1)

Reference: Wikipedia (Circular Sector)