A PreLesson of Pythagorean Theorem

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A Pre-Lesson of Pythagorean Theorem
by Lilian Wong
Mathematics Grade Seven
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What's in the pictures?
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Did you say
Manhole Cover ?
According to Webster Dictionary, manhole is a
hole through which one may go especially to gain
access to an underground or enclosed structure.
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What do all manhole covers have in common?
THEY ARE ALL
ROUND
WHY???
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Your goal now is to investigate the question
WHY ARE MANHOLES ROUND?
Working in groups of 4, use Worksheet 1 to help
you figure out this problem.
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References

• http//www.xanga.com/skin.asp?userstreetphotos
• http//www.carriagetradepress.com/archivequilts.ht
  ml
• www.cfa-hq.org/members/composites2001/
  Comp2001/T045.pdf
• http//www.danheller.com/manholes.html
• http//www.webster.com/cgi-bin/dictionary