Circumradius of the rectangle (original) (raw)

Last Updated : 11 Jul, 2025

Here we have a rectangle of length **l & breadth **b. We have to find the circumradius of the rectangle.

**Examples:

Input : l = 3, b = 4 Output :2.5

Input :l = 10, b = 12 Output :3.95227774224

**Approach:
From the diagram, we can clearly understand the circumradius **r is half of the diagonal of the rectangle.

r = \sqrt(l^2 + b^2)/2

**Below is the implementation of the above approach:

C++ `

// C++ Program to find the radius // of the circumcircle of the given rectangle

#include <bits/stdc++.h> using namespace std;

// Function to find the radius // of the circumcircle float findRadiusOfcircumcircle(float l, float b) {

// the sides cannot be negative
if (l < 0 || b < 0)
    return -1;

// Radius of the circumcircle
float radius = sqrt(pow(l, 2) + pow(b, 2)) / 2;

// Return the radius
return radius;

}

// Driver code int main() {

// Get the sides of the triangle
float l = 4, b = 3;
// Find the radius of the circumcircle
cout << findRadiusOfcircumcircle(l, b) << endl;

return 0;

}

C

// C Program to find the radius // of the circumcircle of the given rectangle #include <stdio.h> #include <math.h>

// Function to find the radius // of the circumcircle float findRadiusOfcircumcircle(float l, float b) {

// the sides cannot be negative
if (l < 0 || b < 0)
    return -1;

// Radius of the circumcircle
float radius = sqrt(pow(l, 2) + pow(b, 2)) / 2;

// Return the radius
return radius;

}

// Driver code int main() {

// Get the sides of the triangle
float l = 4, b = 3;

// Find the radius of the circumcircle
printf("%f\n",findRadiusOfcircumcircle(l, b));
return 0;

}

Java

// Java Program to find the radius // of the circumcircle of the given // rectangle import java.util.; import java.lang.; import java.io.*;

class GFG {

// Function to find the radius // of the circumcircle static float findRadiusOfcircumcircle(float l, float b) {

// the sides cannot be negative
if (l < 0 || b < 0)
    return -1;

// Radius of the circumcircle
float radius = (float) Math.sqrt(Math.pow(l, 2) +
                       Math.pow(b, 2)) / 2;

// Return the radius
return radius;

}

// Driver code public static void main(String args[]) {

// Get the sides of the triangle
float l = 4, b = 3;
// Find the radius of the circumcircle
System.out.println(findRadiusOfcircumcircle(l, b));

} }

// This code is contributed by Subhadeep

Python

Python Program to find the

radius of the circumcircle

of the given rectangle

import math

Function to find the radius

of the circumcircle

def findRadiusOfcircumcircle(l, b):

# the sides cannot be negative
if (l < 0 or b < 0):
    return -1;

# Radius of the circumcircle
radius = (math.sqrt(pow(l, 2) + 
                    pow(b, 2)) / 2);

# Return the radius
return radius;

Driver code

Get the sides of the triangle

l = 4; b = 3;

Find the radius of the circumcircle

print(findRadiusOfcircumcircle(l, b));

This code is contributed

by Shivi_Aggarwal

C#

// C# Program to find the radius // of the circumcircle of the // given rectangle using System;

class GFG {

// Function to find the radius // of the circumcircle static float findRadiusOfcircumcircle(float l, float b) {

// the sides cannot be negative
if (l < 0 || b < 0)
    return -1;

// Radius of the circumcircle
float radius = (float) Math.Sqrt(Math.Pow(l, 2) +
                       Math.Pow(b, 2)) / 2;

// Return the radius
return radius;

}

// Driver code public static void Main() {

// Get the sides of the triangle
float l = 4, b = 3;

// Find the radius of the circumcircle
Console.WriteLine(findRadiusOfcircumcircle(l, b));

} }

// This code is contributed by anuj_67

JavaScript

PHP

`

**Output:

2.5

**Time Complexity: O(1)

**Auxiliary Space: O(1)