# Calculate area of a circle in Java

###### Input - Question 13

In this question, we will see how to input the radius of a circle in Java programming using the java input and find its area. To know more about java input click on the java input lesson.

**Q13)** Write a program in Java to input the radius of a circle and find its area. Area of a circle is πr^{2}. Where r is the radius and the value of π (pie) is 22/7 or 3.142

Formula: area = 3.142 * r * r

#### Program

```
import java.util.Scanner;
public class Q13
{
public static void main(String args[])
{
float r,a;
Scanner sc=new Scanner(System.in);
System.out.print("Enter radius of a circle ");
r=sc.nextFloat();
a=3.142f*r*r;
System.out.println("Area=" + a);
}
}
```

#### Output

Enter radius of a circle 5 Area=78.55