Program to find the Area and Perimeter of a Semicircle

Given the radius of the semicircle as r, the task is to find out the Area and Perimeter of that semicircle.
Examples:

Input: r = 10
Output: Area = 157.00, Perimeter = 31.4

Input: r = 25
Output: Area =981.250000, Perimeter = 78.500000

Approach:
In mathematics, a semicircle is a one-dimensional locus of points that forms half of a circle. The area of a semicircle is half the area of the circle from which it is made. Any diameter of a circle cuts it into two equal semicircles.

Area of Semi-Circle = ¹?₂ * ? *r²
Perimeter of Semi-Circle = ? *r
where “r” is the radius of the semicircle. 

Below is the implementation of the above approach:

C++

// C++ program to find the
// Area and Perimeter of a Semicircle

#include <iostream>
using namespace std;

// Function for calculating the area
float area(float r)
{
    // Formula for finding the area
    return (0.5)*(3.14)*(r * r);
}

// Function for calculating the perimeter
float perimeter(float r)
{
    // Formula for finding the perimeter
    return (3.14)*(r);
}

// driver code
int main()
{

    // Get the radius
    int r = 10;

    // Find the area
    cout << "The Area of Semicircle: "
         << area(r) << endl;

    // Find the perimeter
    cout << "The Perimeter of Semicircle: "
         << perimeter(r) << endl;

    return 0;
}

C

// C program to find the
// Area and Perimeter of a Semicircle

#include <stdio.h>

// Function for calculating the area
float area(float r)
{
    // Formula for finding the area
    return (0.5)*(3.14)*(r * r);
}

// Function for calculating the perimeter
float perimeter(float r)
{
    // Formula for finding the perimeter
    return (3.14)*(r);
}

// driver code
int main()
{

    // Get the radius
    float r = 10;

    // Find the area
    printf("The Area of Semicircle: %f\n",
        area(r));

    // Find the perimeter
    printf("The Perimeter of Semicircle: %f\n",
        perimeter(r));
    return 0;
}

Java

// Java program to find the
// Area and Perimeter of a Semicircle

import java.io.*;

class GFG {

// Function for calculating the area
static float area(float r)
{
    // Formula for finding the area
    return (float)((0.5)*(3.14)*(r * r));
}

// Function for calculating the perimeter
static float perimeter(float r)
{
    // Formula for finding the perimeter
    return (float)((3.14)*(r));
}

// driver code

    public static void main (String[] args) {
    // Get the radius
    float r = 10;

    // Find the area
    System.out.println("The Area of Semicircle: "+
        area(r));

    // Find the perimeter
    System.out.println("The Perimeter of Semicircle:"+
        +perimeter(r));
    }
}
 // This code is contributed
// by anuj_67..

Python3

# Python3 program to find the
# Area and Perimeter of a Semicircle

# Function for calculating the area
def area(r):

    # Formula for finding the area
    return (0.5)*(3.14)*(r * r)

#Function for calculating the perimeter
def perimeter(r):

    #Formula for finding the perimeter
    return (3.14)*(r)

# driver code
if __name__=='__main__':
    # Get the radius
    r = 10

    # Find the area
    print ("The Area of Semicircle: "
           ,area(r))

    # Find the perimeter
    print ("The Perimeter of Semicircle: "
           ,perimeter(r))

# This code is contributed by
# SURENDRA_GANGWAR

C#

// C# program to find the
// Area and Perimeter of a Semicircle
using System;

class GFG {

// Function for calculating the area
static float area(float r)
{
    // Formula for finding the area
    return (float)((0.5)*(3.14)*(r * r));
}

// Function for calculating the perimeter
static float perimeter(float r)
{
    // Formula for finding the perimeter
    return (float)((3.14)*(r));
}

// Driver Code
public static void Main()
{
    // Get the radius
    float r = 10;

    // Find the area
    Console.WriteLine("The Area of Semicircle: " +
                                         area(r));

    // Find the perimeter
    Console.WriteLine("The Perimeter of Semicircle:" +
                                        perimeter(r));
}
}

// This code is contributed
// by Akanksha Rai(Abby_akku)

PHP

<?php
// PHP program to find the
// Area and Perimeter of a Semicircle

// Function for calculating the area
function area($r)
{
    // Formula for finding the area
    return (0.5) * (3.14) * ($r * $r);
}

// Function for calculating
// the perimeter
function perimeter($r)
{
    // Formula for finding
    // the perimeter
    return (3.14) * ($r);
}

// Driver code

// Get the radius
$r = 10;

// Find the area
echo "The Area of Semicircle: ",
    area($r),"\n" ;

// Find the perimeter
echo "The Perimeter of Semicircle: ",
    perimeter($r),"\n" ;

// This code is contributed
// by ANKITRAI1
?>

Javascript

<script>
// javascript program to find the
// Area and Perimeter of a Semicircle

// Function for calculating the area
    function area(r) {
        // Formula for finding the area
        return  ((0.5) * (3.14) * (r * r));
    }

    // Function for calculating the perimeter
    function perimeter(r) {
        // Formula for finding the perimeter
        return  ((3.14) * (r));
    }

    // driver code


        // Get the radius
        var r = 10;

        // Find the area
        document.write("The Area of Semicircle: " + area(r).toFixed(6)+"<br/>");

        // Find the perimeter
        document.write("The Perimeter of Semicircle: " +
        perimeter(r).toFixed(6)+"<br/>");

// This code contributed by gauravrajput1

</script>

Output:

The Area of Semicircle: 157.000000
The Perimeter of Semicircle: 31.400000

Time Complexity: O(1), since there is no loop or recursion.

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