What are the three most common sizes of floppy disks?

The three most common sizes of floppy disks are indeed 8 inch, 5 ¼ inch, and 3 ½ inch. The 8-inch floppy disk was one of the first disk formats used in the early days of personal computing, primarily used in mainframe computers. The 5 ¼ inch disk became popular in the late 1970s and continued through the 1980s for personal computers. Lastly, the 3 ½ inch disk became dominant in the 1990s due to its sturdy plastic casing and higher storage capacity, ultimately leading to the decline of the larger formats. Each of these sizes reflects a significant evolution in how data was stored and accessed during different eras in computing history, marking the transition from larger, less portable formats to more compact and user-friendly designs.