```
import java.util.*;
public class Main
{
public static void main(String[] args)
{
double a, b;
double area, perimeter, diagonal;
System.out.print("Enter the width: ");
a = Double.parseDouble(new Scanner(System.in).nextLine());
System.out.print("Enter the height: ");
b = Double.parseDouble(new Scanner(System.in).nextLine());
perimeter = a * 2 + b * 2;
System.out.printf("Perimeter: %1$s" + "\r\n", perimeter);
area = a * b;
System.out.printf("Area: %1$s" + "\r\n", area);
diagonal = Math.sqrt(a * a + b * b);
System.out.printf("Diagonal: %1$s" + "\r\n", diagonal);
}
}
```