Java Program to Find Area of Circle,Triangle,Rectangle,Square and all others

This topic demonstrates about how to programatically find out the area of basic shapes using java program.

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Example - Find the area of circle using java program

Steps

1. Accept the radius from user
2. Initialize the value of pi = 3.1415 in float form
3. Use above mentioned formula in the chart to calculate area of circle

import java.util.Scanner;

public class AreaOfCircleEx 
{
	public static void main(String[] args) 
	{
		int radius;
		float PI = 3.1415f,area;
		Scanner scan = new Scanner(System.in);
		
		System.out.print("Enter radius : ");
		radius = scan.nextInt();
	
		area = PI * (radius * radius); // pi * r square
		System.err.println("Area of circle with radius "+radius+" is "+area);
	}
}

Output

Note : You can also use the PI constant from Math class as

float PI = (float) Math.PI; // typecast required because it is double constant

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Example - Find the Area of Rectangle using java program

Steps

1. Accept the length and breadth (width) from user
2. Use above mentioned formula in the chart to calculate area of Rectange
3. Display the formula result to user

Note : Breadth value should be greater than Length value.

Program

import java.util.Scanner;
public class AreaOfRectangleEx 
{
	public static void main(String[] args)
	{
		Scanner scan = new Scanner(System.in);
		int length,breadth,area;
		
		System.out.print("Enter Length and Breadth : ");
		length = scan.nextInt();
		breadth = scan.nextInt();
		area = length * breadth;
		System.out.print("Area of Rectangle is : "+area);
	}
}

Output