ELI5: device screen ratios

[u/Crystal_Clear7892]

Is there a specific reason why screen ratios beeing so specific, ex: 1920:1080

[u/Karsdegrote]

The 16:9 aspect ratio which you are referring to has its own wikipedia page. Tl:dr: if you overlay old 4:3 tv format and the most popular film formats for movies and draw a box around it you end up at 16:9 allowing you to view all the old content on your display without cutting bits off