Find the type of triangle from the given sides

Given three integers A, B, and C which denotes the sides of a triangle, the task is to check that the triangle is a right-angled, acute-angled or obtuse-angled triangle.

Examples:

Input: A = 1, B = 4, C = 3
Output: Obtuse-angled Triangle
Explanation:
Triangle with the sides 1, 2 and 3 is an obtuse-angled triangle

Input: A = 2, B = 2, C = 2
Output: Acute-angled Triangle
Explanation:
Triangle with the sides 2, 2, and 2 is an acute-angled triangle

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The idea is to use the facts from the cosine law to check the type of triangle using this formulae –
$c^2 &= a^2 + b^2 - 2*a*b*cos\gamma$
It generalizes the Pythagorean Theorum, which states that for a right-angled triangle square of the hypotenuse is equal to the sum of squares of the base and height of the triangle, which is $c^2 &= a^2 + b^2$

Similarly, It can be observed that
For acute-angled triangle
$c^2 \textless a^2 + b^2$
For Obtuse-angled triangle
$c^2 \textgreater a^2 + b^2$

Below is the implementation of the above approach:

C++

// C++ implementation to find 
// the type of triangle with 
// the help of the sides 
  
#include <bits/stdc++.h> 
using namespace std; 
  
// Function to find the type of 
// triangle with the help of sides 
void checkTypeOfTriangle(int a,  
                int b, int c){ 
    int sqa = pow(a, 2); 
    int sqb = pow(b, 2); 
    int sqc = pow(c, 2); 
      
    if (sqa == sqa + sqb ||  
        sqb == sqa + sqc ||  
        sqc == sqa + sqb){ 
        cout << "Right-angled Triangle"; 
    } 
    else if(sqa > sqc + sqb || 
            sqb > sqa + sqc || 
            sqc > sqa + sqb){ 
        cout << "Obtuse-angled Triangle"; 
    } 
    else{ 
        cout << "Acute-angled Triangle"; 
    } 
} 
  
// Driver Code 
int main() 
{ 
    int a, b, c; 
    a = 2; 
    b = 2;  
    c = 2; 
      
    // Function Call 
    checkTypeOfTriangle(a, b, c); 
    return 0; 
} 

Java

// Java implementation to find 
// the type of triangle with 
// the help of the sides 
import java.util.*; 
  
class GFG 
{ 
  
// Function to find the type of 
// triangle with the help of sides 
static void checkTypeOfTriangle(int a,  
                int b, int c){ 
    int sqa = (int)Math.pow(a, 2); 
    int sqb = (int)Math.pow(b, 2); 
    int sqc = (int)Math.pow(c, 2); 
      
    if (sqa == sqa + sqb ||  
        sqb == sqa + sqc ||  
        sqc == sqa + sqb){ 
        System.out.print("Right-angled Triangle"); 
    } 
    else if(sqa > sqc + sqb || 
            sqb > sqa + sqc || 
            sqc > sqa + sqb){ 
        System.out.print("Obtuse-angled Triangle"); 
    } 
    else{ 
        System.out.print( "Acute-angled Triangle"); 
    } 
} 
  
// Driver Code  
public static void main (String []args) 
{ 
    int a, b, c; 
    a = 2; 
    b = 2;  
    c = 2; 
      
    // Function Call 
    checkTypeOfTriangle(a, b, c); 
} 
} 
  
// This code is contribute by chitranayal 

Python3

# Python3 implementation to find 
# the type of triangle with 
# the help of the sides 
  
# Function to find the type of 
# triangle with the help of sides 
def checkTypeOfTriangle(a,b,c): 
    sqa = pow(a, 2) 
    sqb = pow(b, 2) 
    sqc = pow(c, 2) 
  
    if (sqa == sqa + sqb or
        sqb == sqa + sqc or
        sqc == sqa + sqb): 
        print("Right-angled Triangle") 
  
    elif(sqa > sqc + sqb or
            sqb > sqa + sqc or
            sqc > sqa + sqb): 
        print("Obtuse-angled Triangle") 
  
    else: 
        print("Acute-angled Triangle") 
  
# Driver Code 
if __name__ == '__main__': 
    a = 2
    b = 2
    c = 2
  
    # Function Call 
    checkTypeOfTriangle(a, b, c) 
  
# This code is contributed by mohit kumar 29 

C#

// C# implementation to find 
// the type of triangle with 
// the help of the sides 
using System; 
  
class GFG 
{ 
   
// Function to find the type of 
// triangle with the help of sides 
static void checkTypeOfTriangle(int a,  
                int b, int c){ 
    int sqa = (int)Math.Pow(a, 2); 
    int sqb = (int)Math.Pow(b, 2); 
    int sqc = (int)Math.Pow(c, 2); 
       
    if (sqa == sqa + sqb ||  
        sqb == sqa + sqc ||  
        sqc == sqa + sqb){ 
        Console.Write("Right-angled Triangle"); 
    } 
    else if(sqa > sqc + sqb || 
            sqb > sqa + sqc || 
            sqc > sqa + sqb){ 
        Console.Write("Obtuse-angled Triangle"); 
    } 
    else{ 
        Console.Write( "Acute-angled Triangle"); 
    } 
} 
   
// Driver Code  
public static void Main(String []args) 
{ 
    int a, b, c; 
    a = 2; 
    b = 2;  
    c = 2; 
       
    // Function Call 
    checkTypeOfTriangle(a, b, c); 
} 
} 
  
// This code is contributed by 29AjayKumar 

Output:

Acute-angled Triangle

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My Personal Notes

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

C++

Java

Python3

C#

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