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Square Metre

335 words

There was a poster sale at uni. And I overheard people talking about the poster sizes after they got a flyer for it. The A0 format was mentioned and a little discussion started about how large it is.

Which of course seems completely unnecessary if you know what ‘A’ paper formats are. Their aspect ratio is 1:√2 and the sizes are fixed by A0 covering an area of one square metre with an increase of the number corresponding to cutting the paper in half at the middle of its longer edge.

But of course many people don’t know about these simple facts which give us a paper format that is particularly convenient to fold and doesn’t have the most æsthetic of looks. And thus their discussion soon arrived at a point where the ‘huge’ A0 was estimated to be around 2,5m×2,5m which in turn was supposed to be about 4m2.

And, sure, I’m a mathematician, so I may be a bit better with numbers than other people. But the only thing that’s a matter of maths here is that 2,5m×2,5m is 6,25m2 which is more than 50% off their estimate which surely came from bad rounding and underestimating the power of squaring.

Everything else they got wrong just seems like a lack of common sense or the inability to think straight for a few seconds. Yup, common sense, i.e. something that mathematicians aren’t that great at. And perhaps our friends from physics are much more keener at. Even if you don’t know that A0 is a square metre, people surely know the size of A4 because they write on it every single day. Even without the precise 297mm×210mm measurements at hand, 30cm×20cm won’t be a bad approximation that can easily be guessed. Also, people do know that A3 is twice the size of A4 and that the series continues in that way.

So how can they – university students even – possibly end up guessing that A0 is a 6m2 square?

November 1, 2007, 18:20


Comment by Thomas: User icon

The problem with common sense is that it is not very common…

November 2, 2007, 13:46

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