Calculate Circle Area.

/*Calculate Circle Area In Java example*/
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import java.util.Scanner;
public class CalculateCircleArea
{
        public static void main(String[] args)
       {
                float radius = 0;
Scanner sc = new Scanner(System.in);
                System.out.println("Please enter radius of a circle:");
                radius = sc.nextFloat();
                double area = Math.PI * radius * radius;
                System.out.println("Area of a circle is :" + area);
       }
}

Math.PI returns the pi value of 3.141592653589793.

● Save the file as SimpleInterest.java 
● When the program is run, the following output is displayed:

Output

Please enter radius of a circle:
12
Area of a circle is :452.3893421169302