Tuesday, June 10, 2008

Anecdotes and Rationale About Why Math is Important

Anecdote #1 – The Curtain Ring Problem

A couple I knew, college educated I might add, needed to make a curtain for a closet opening. Curtain rings come in packages of 12. This might seem very practical, 12 being a dozen and all.

So, the couple divided the fabric into 12 spaces, easily done by folding in halves and thirds.  When they attached the rings, they found that they were one ring short, thus no ring for the end.  They discovered that they needed 13 rings when the curtain has 12 spaces.  Alas, they just left the curtain flapping.  See the diagram. 

Clearly they were using a mathematical approach, but unfortunately, it wasn’t the best one.

Using 12 rings means the curtain needs to be folded into 11 spaces, and 11 is a prime number, meaning it has no other factors except itself and 1. Therefore the folding method to determine the spacing of the rings is impractical. The curtain needs to be measured, then the measurement number needs to be divided by 11 or alternately multiplied by 1/11.

Example: Let us say that the fabric is 5ft. wide.














Yes, I used the frightening "fraction" to help solve the problem. The result: A curtain that doesn’t look ridiculous, lot of money saved. And some say that math isn’t practical and they have no use for it!

2 comments:

Barry Garelick said...

Or you can just use 11 rings giving you ten intervals, so the division is much easier, and donate the extra ring to the Goodwill.

MathChique said...

Barry is right. The division by 11 is tricky. If you use his idea, then try the metric side of the tape measure and the problem will become super easy.

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