Conditional Constructs in Java

Chapter 8

Conditional Constructs in Java

Class 10 - Logix Kips ICSE Computer Applications with BlueJ

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Java Program: Compute the perimeter and area of a triangle using Heron’s formula

27. Write a program in Java to compute the perimeter and area of a triangle, with its three sides given as a, b, and c using the following formulas:

Java

import java.util.Scanner;
 
public class TrianglePerimeterArea {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 
        double a, b, c;
        double perimeter, s, area;
 
        System.out.print("Enter side a: ");
        a = sc.nextDouble();
 
        System.out.print("Enter side b: ");
        b = sc.nextDouble();
 
        System.out.print("Enter side c: ");
        c = sc.nextDouble();
 
        // Calculate perimeter
        perimeter = a + b + c;
 
        // Calculate semi-perimeter
        s = perimeter / 2;
 
        // Calculate area using Heron's formula
        area = Math.sqrt(s * (s - a) * (s - b) * (s - c));
 
        System.out.println("\nPerimeter of the triangle = " + perimeter);
        System.out.println("Area of the triangle = " + area);
    }
}

Output

Sample Output 
Enter side a: 3
Enter side b: 4
Enter side c: 5

Perimeter of the triangle = 12.0
Area of the triangle = 6.0

✅ Explanation

The program takes three sides as input using the Scanner class.
Perimeter is calculated by adding all sides.
Semi-perimeter (s) is half of the perimeter.
Area is calculated using Math.sqrt() and Heron’s formula.
Suitable for school exams, assignments, and practicals.