Double Learn programming Visual Basic (VB.net)

Imports System

Public Class exercise55
    Public Shared Sub Main()
        Dim a, b As Double
        Dim area, perimeter, diagonal As Double
        Console.Write("Enter the width: ")
        a = Convert.ToDouble(Console.ReadLine())
        Console.Write("Enter the height: ")
        b = Convert.ToDouble(Console.ReadLine())
        perimeter = a * 2 + b * 2
        Console.WriteLine("Perimeter: {0}", perimeter)
        area = a * b
        Console.WriteLine("Area: {0}", area)
        diagonal = Math.Sqrt(a * a + b * b)
        Console.WriteLine("Diagonal: {0}", diagonal)
    End Sub
End Class