Java Program for Program to find area of a circle

Area of a circle can simply be evaluated using following formula.

Area = pi * r2
where r is radius of circle 

Java

// Java program to find area
// of circle

class Test
{
    static final double PI = Math.PI;

    static double findArea(int r)
    {
       return PI * Math.pow(r, 2);
    }

    // Driver method
    public static void main(String[] args)
    {
        System.out.println("Area is " +  findArea(5));
    }
}

Time Complexity: O(log n) since using inbuilt Math.pow function

Auxiliary Space : O(1)

Please refer complete article on Program to find area of a circle for more details!