Madan wrote:
>There are some areas in maths where fractions are
>useful
>for example
>* its better to express pi as 22/7 instead of 3.14,
>since 22/7 is more precise.

Neither is precise. 22/7 is 3.1429 (or, to be really precise, 3.142857, with
the last 6 digits recurring), whereas pi is 3.1416. So, yes, 22/7 is
marginally closer than 3.14. One more decimal place (3.142) and you're
certainly close enough for government work.

>* volume of pyramid = 1/3 * base-area * height,  if we
>use 0.33, then we may not get the correct volume.

That shouldn't, however, be expressed as a fraction. The better formula is
(base-area*height)/3. In that case, we have an integer divisor, rather than
a fractional multiplier.

Bill Potts, CMS
Roseville, CA
http://metric1.org [SI Navigator]

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