Fitting to Screen Adobe Illustrator to premiere pro?

So I am working on a video on Adobe Premiere Pro. 

I have edited a slide on Adobe illustrator which I have imported into the project. 

When I double click on the source monitor tab, it displays as full size and fits to screen. 

When I import it onto the timeline and play in the program monitor it cuts off the top and bottom and displays them as blank as it the original document was too landscape to fit on the screen. Kind of like trying to fit a rectangle into a square. 

I also have had a problem with having blank spaces when importing screenshots into my videos using premiere pro. 

What dimensions will I need to set when editing the original illustrator file? At first I selected a TV style document thinking that would be the best bet to fit to screen on premiere pro. 

Thanks in advance!