WPF TextBlock font resize to fill available space in a Grid

Question

I have some text that is displayed at run time in a textblock. I want the font size to be the biggest it can be to fill the area that is given. I think I have the textblock

Answer 1

I found a great way to do this using ViewBox:

 
    
        
        
        
        
    
    
        
        
    
    
            
    

    
        This is some text