Okay so I know that 8k , 4K are UHD and 1080p and 720 are HD, I know that much but I'm confused on how that ties in with screen size or tv size
Let's say I have a 720p tv it's like 40 inches but I also see 40inch TVs that are 720p how does that work
Also I know it's #### X 720p does the last set of numbers mean that's what the definition is. Hope that's not too confusing
1) 720p refers actually to the number of horizontal LINES. It's usually actually 768p (768 lines). The "p" just means progressive as. They used to be interlaced (skip lines then go back to prevent fluctuating brightness in CRT "tube" screens).
2) 2K, 4K etc mean the number of VERTICAL lines approximately. For 4K which has "3840x2160" this means almost 4K vertical lines and 2K horizontal lines.
We could have also called 4K "2160p" but that's not as catchy.