Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site rti-sel.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!unc!mcnc!rti-sel!trt
From: trt@rti-sel.UUCP (Tom Truscott)
Newsgroups: net.math
Subject: Re: significant digits
Message-ID: <382@rti-sel.UUCP>
Date: Tue, 27-Aug-85 10:53:42 EDT
Article-I.D.: rti-sel.382
Posted: Tue Aug 27 10:53:42 1985
Date-Received: Wed, 28-Aug-85 10:47:53 EDT
References: <2244@utcsstat.UUCP>
Organization: Research Triangle Institute, NC
Lines: 26

> >... "What's the area of a table 3 meters wide by 4
> >meters long?"  I poked around with various counter-probes like, "Do you
> >mean the area of just the top surface, or the top and bottom combined?" and
> >then came up with the obvious answer; 12 meters^2.

I cannot see what is wrong with the 'obvious answer',
and I cannot recall reading in any textbook the justifications
used for the answer '1x10^1 m^2'.  Even if we assume
inexact measurements '12 m^2' is the best integral estimate.
Perhaps I could be enlightened.

If I tell you that a right triangle has sides of length 3 and 4
and ask you for the length of the hypotenuse are you going
to answer '5' or are you going to worry about errors in measurement?
If I ask you 'What is 6+7' are you going to answer 1x10^1??

If I ask you for 'the area of a table' are you going to
chide me for asking a meaningless question?
Are you going to assume I meant the area
of an imaginary plane which has a good fit with the
approximate surface of the table?
Are you going to assume I meant the area of an idealized table
which is flat and rectangular,
and then assume I used a ruler accurate only to a half meter??
If that is the answer, then I am wrong and proud of it.
	Tom Truscott