Even a cheap tablet with no official specs normally mentions the screen resolution on the box, didn't yours?

If not, then you could visit a web page like http://www.whatismyscreenresolution.com/ (there are many other similar websites out there) or install an app like Android System Info that will tell you your resolution as well as your DPI.

The DPI is just a measurement of how many pixels there are on an inch of your screen, so if you know your screen resolution, you can measure the size of your screen and calculate the DPI from  there to get the actual density.

What is my lcd density?
When travelling on flights where meals are included, travellers who need special meals, such as vegetarian or kosher, are, in my experience, typically required to make such a request by phone.

For the traveller, this might mean a 15 minute hold, followed by a 1 minute phonecall.  After all, the operator simply needs to make an entry into a database somewhere.

Why don't airlines offer seem to offer travellers the option to select their special meal request through an online interface?  Or do I just have the bad luck to happen to fly with airlines where this request can only be made by phone?

Examples: Air Transat, Korean Air both require to contact the service centre by telephone.
