Largest square that can be inscribed in a semicircle - Coding

Given a semicircle with radius r, we have to find the largest square that can be inscribed in the semicircle, with base lying on the diameter.

Examples:

Input: r = 5
Output: 20

Input: r = 8
Output: 51.2

Approach: Let r be the radius of the semicircle & a be the side length of the square.
From the figure we can see that, centre of the circle is also the midpoint of the base of the square. So in the right angled triangle AOB, from Pythagoras Theorem:

a^2 + (a/2)^2 = r^2
5*(a^2/4) = r^2
a^2 = 4*(r^2/5) i.e. area of the square

Below is the implementation of the above approach:

C++

<?php
// PHP Program to find the 
// biggest square which can be 
// inscribed within the semicircle
 
// Function to find the area
// of the square
function squarearea($r)
{
 
    // the radius cannot be negative
    if ($r < 0)
        return -1;
 
    // area of the square
    $a = 4 * (pow($r, 2) / 5);
 
    return $a;
}
 
// Driver code
$r = 5;
echo squarearea($r);
 
// This code is contributed 
// by Shivi_Aggarwal
?>

Javascript

<script>
 
// javascript Program to find the biggest square
// which can be inscribed within the semicircle
 
// Function to find the area
// of the square
function squarearea(r)
{
 
    // the radius cannot be negative
    if (r < 0)
        return -1;
 
    // area of the square
    var a = 4 * (Math.pow(r, 2) / 5);
 
    return a;
}
 
// Driver code
var r = 5;
document.write( squarearea(r));
 
// This code contributed by Princi Singh 
 
</script>

Output:

Time Complexity: O(1)

Auxiliary Space: O(1)

Reffered: https://www.geeksforgeeks.org

DSA

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Type:	Geek
Category:	Coding
Sub Category:	Tutorial
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