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Program to find area of a circle

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Given the radius of a circle, find the area of that circle.

The area of a circle can simply be evaluated using the following formula.
 

Area-of-circle


 

Area = \pi r^2

where r is radius of circle and it maybe in float because value of pie is 3.14 

 

Approach: Using the given radius, find the area using the above formula: (pi * r * r) and print the result in float.
 

C++

// C++ program to find area
// of circle
#include <iostream>
const double pi = 3.14159265358979323846;
using namespace std;
  
// function to calculate the area of circle
float findArea(float r)
{
    return (pi * r * r);
}
// driver code
int main()
{
    float r, Area;
    r = 5;
  
    // function calling
    Area = findArea(r);
    // displaying the area
    cout << "Area of Circle is :" << Area;
    return 0;
}

                    

C

// C program to find area
// of circle
#include <stdio.h>
#include <math.h>
#define PI 3.142
  
double findArea(int r)
{
   return PI * pow(r, 2);
}
  
int main()
{
    printf("Area is %f", findArea(5));
    return 0;
}

                    

Java

// Java program to find area
// of circle
      
class Test
{
    static final double PI = Math.PI;
           
    static double findArea(int r)
    {
       return PI * Math.pow(r, 2);
    }
           
    // Driver method
    public static void main(String[] args) 
    {
        System.out.println("Area is " +  findArea(5));
    }
}

                    

Python3

# Python3 program to find Area of a circle
  
def findArea(r):
    PI = 3.142
    return PI * (r*r);
  
# Driver method
print("Area is %.6f" % findArea(5));
  
# This code is contributed by Chinmoy Lenka

                    

C#

// C# program to find area of circle
using System;
  
class GFG
{
    static double PI = Math.PI;
          
    static double findArea(int r)
    {
    return PI * Math.Pow(r, 2);
    }
          
    // Driver method
    static void Main() 
    {
        Console.Write("Area is " + findArea(5));
    }
}
  
// This code is contributed by Sam007.

                    

PHP

<?php
// PHP program to find area
// of circle
       
function findArea( $r)
{
    $PI =3.142;
    return $PI * pow($r, 2);
}
   
// Driver Code
echo("Area is ");
echo(findArea(5));
return 0;
  
// This code is contributed by vt_m.
?>

                    

Javascript

<script>
  
// Javascript program to find area 
// of circle 
  
let pi = 3.14159265358979323846;  
  
// function to calculate the area of circle 
function findArea(r) 
    return (pi * r * r); 
  
// Driver code 
    let r, Area; 
    r = 5; 
  
    // function calling 
    Area = findArea(r); 
      
    // displaying the area 
    document.write("Area of Circle is :" + Area); 
      
// This code is contributed by Mayank Tyagi
  
</script>

                    

Output
Area of Circle is :78.5398

Time Complexity: O(1)
Auxiliary Space: O(1), since no extra space has been taken.
 



Last Updated : 16 Feb, 2023
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