Aspect Ratio

Aspect Ratio is an image projection attribute that describes the proportional relationship between the width of an image and its height.

10" tablet (9.7" display) 
          4:3

Smartphone (4.7" display)
         16:9

Leaderboard Ad
          4:3

HDTV  
         16:9



Interlaced scanning is simply displaying alternating sets of lines. Progressive video on the other hand displays the entire image in 1/60th of a second.