Find area of triangle (three sides) using hero formula ( java & example)

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  • Given three sides of triangle, find the area of triangle using hero’s formula.
  • Suppose a, b and c are the sides of triangle.
  • We will read the input from console using Scanner class.

1. Algorithm: find area of triangle using hero’s formula in java (example)

  1. Read the sides of triangle from console.
  2. Check given sides of triangle can form a valid triangle.
    • Any two sides of a triangle should be greater than third side.
    • If yes, We will find out the area of triangle.
  3. Find the semi perimeter of triangle.
    •  semiPerimeter = (a+ b + c)/2
  4. Find out the area of triangle using semi perimeter
    • Area = sqrt(s(s-a)(s-b)(s-c))
area triangle side hero java example
Fig 1: Area of triangle using hero formula

2. Program: calculate area of triangle using hero formula in java (example)

package org.learn;
 
import java.util.Scanner;
 
public class AreaOfTriangleHero {
 
    public static void main(String[] args) {
        try (Scanner scanner = new Scanner(System.in)) {
            System.out.printf("Enter length of first side of triangle : ");
            double side1 = scanner.nextDouble();       
             
            System.out.printf("Enter length of second side of triangle : ");
            double side2 = scanner.nextDouble();   
             
            System.out.printf("Enter length of third side of triangle : ");
            double side3 = scanner.nextDouble();       
                 
            boolean isValidTriangle = (side1 + side2) > side3 && (side1 + side3) > side2 &&
                                                (side1 + side3) > side2;
            if(!isValidTriangle) {
                System.out.println("Side of triangle are invalid");
                return;
            }
            //semiPerimeter s = (a+b+c) / 2
            //where a,b,c are sides of triangle
            double semiPerimeter = (side1 + side2 + side3)/2;  
            //Area = sqrt(s(s-a)(s-b)(s-c))
            double area =  Math.sqrt(semiPerimeter*(semiPerimeter-side1)
                                    *(semiPerimeter-side2)*(semiPerimeter-side3));
            System.out.printf("Area of triangle is : %4.2f",area);
        }
    }
}

3. Output: Area of triangle using hero’s formula in java (example).

1. Enter length of first side of triangle : 5
2. Enter length of second side of triangle : 6
3. Enter length of third side of triangle : 12
4. Sides of triangle are invalid
 
1. Enter length of first side of triangle : 4
2. Enter length of second side of triangle : 8
3. Enter length of third side of triangle : 10
4. Area of triangle is : 15.20
 
1. Enter length of first side of triangle : 5
2. Enter length of second side of triangle : 7
3. Enter length of third side of triangle : 10
4. Area of triangle is : 16.25

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