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subtle compass for the busy maths teacher...

when I was a kid, I had a maths teacher who had an original pair of compasses, she was quite proud of it and told the class her solution was cheaper and easier to carry from classroom to classroom than traditional pair of compasses...

here's her solution:

need more explanation?

6 comments

Feb 1, 2012. 3:20 PMtechnofossil says:

It's a good trick to know. Thanks for sharing it.

I've used this same type of thing in the past then I needed to draw a circle (or arc) larger than my compass would allow. One thing to keep in mind, don't use a cord that stretches too much, it will make it harder to draw a clean circle.

PS. This isn't English class. If you want to correct his translation, let's do it politely. In English we use a PAIR of scissors even though there is only one tool with two parts. The correct name of the tool is compass (singular) even though it has two arms (like a scissor) but we refer to it in the singular. Probably because any tool used to draw a circle is called a compass (look up beam compass for example http://en.wikipedia.org/wiki/Beam_compass).

Dec 31, 2011. 10:24 PM

escapefromyonkers says:

i thought it was called a compass. But i am not a math person i have a couple and i remember the package saying compass, maybe in france they are called pairs since the older ones that the navigators used , i think they used compasses with the sextant. so maybe they were used in pairs or the two arms of a compass gave the term pair in France. just a guess

Dec 10, 2011. 6:01 PMgeorion says:

a pair is 2------------ where is the other one ??????????

Dec 11, 2011. 2:36 PM

louis perichon (author) says:

sorry, this must be a translation mistake....
isn't the tool you draw circles with called a "pair of compasses"?

I'm french....I should have called this instructable: "subtle compass for the busy maths teacher..."

thanks for this comment...

Dec 11, 2011. 2:31 PM

louis perichon (author) says:

(removed by author or community request)

Dec 11, 2011. 2:34 PM

louis perichon (author) says:

done....