# Program to find area of a circle

Area of a circle can simply be evaluated using following formula. ```Area = pi * r2
where r is radius of circle ```

## C++

 `// C++ program to find area ` `// of circle ` `#include ` `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 ` `#include ` `#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

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Output:

`Area is 78.550000`

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Improved By : vt_m, RamAryan