From: John Beckett 

"Antti Kurenniemi"  wrote
in message news::
> Haven't seen any paper sizes in anything except metric scale in... well
> probably all my life. Though the sizes aren't exactly logical. Most common
> is A4 which is sort of similar to the US Letter size, and it's 297 X 210 mm.
> Can't be an even 300, nooo...

I am rather fond of A4 paper. You probably know the story, but for the
benefit of our imperial friends I will spare no details...

An A0 sheet of paper is one square meter in a rectangle with sides
proportioned so that if you fold the sheet of paper in half (halving the
long side), the result has sides in the same proportion.

Doing the maths shows that the long side is sqrt(2) times longer than the short side.

An A1 sheet of paper is what you get from halving an A0 sheet.

A4 is half A3, which is half A2, which is half A1, which is half A0.

The result is that an A4 sheet is one sixteenth of a square metre, with a
long side that is sqrt(2) times longer than the short side.

Using 80gsm paper (80 grams/square meter weight), an A4 sheet weighs 80/16
= 5 grams.

Not only is an A4 sheet logical, it is elegant as well!

John

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