18
Every screen I have ever heard of is measured from corner to corner. Televisions, LCDs, computer monitors, everything I know of. Always has been. Also, there is a difference is screen size and VIEWABLE screen. For example, if you have a 23" monitor, it may only be 21" viewable. Manufacturers market the total screen size, which is more than the viewable size.
On a 21 inch TV yes on a Computer monitor no
Desktop monitors come in various sizes, typically ranging from about 21 inches to 32 inches diagonally. Common sizes include 24-inch, 27-inch, and 32-inch models, with the measurement referring to the diagonal length of the screen. The size you choose often depends on your workspace and personal preference for viewing comfort.
it almost 20-21 inch
It's cheaper to add a 17 inch monitor to an existing system. In addtion, if the monitor has IR Transmit, that would be even more convenient. You can see this one on Eonon. The cost is very low.http://www.eonon.com/Flip-Down-Monitor-or-DVD-Player/E0618A.html?utm_source=wiki.answers.com&utm_medium=answer&utm_campaign=answer
a 2 or 3 maybe
An 'O' drill bit is a decimal size, 0.3160 inch, which is between 5/16 and 21/64 on the fractional inch scale.
The size restrictions for 62 linear inch luggage on this airline are typically 27 x 21 x 14 inches.
The next total eclipse viewable in the US will be August 21, 2017
21 inch
It is: 21+31+21+31 = 104 inches
A giraffe can clean its ears with its 21-inch tongue!