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7-, 9-Sided Polygons


Date: 9/13/96 at 16:2:31
From: Dee Sypherd
Subject: 7, 9 Sided Polygons

Dear Dr. Math,

What is the name of a 7-sided figure? What is the name of a 9-sided
figure?  Is one of these ever called a septagon?

Thank you,
Mrs. Sypherd's 4th - 6th grade class
Ayr Public School
Ayr, NE


Date: 9/13/96 at 17:7:2
From: Doctor Tom
Subject: Re: 7, 9 Sided Polygons

The "official" names use Greek, not Latin prefixes, so they are 
heptagon and nonagon for 7- and 9-sided figures.

There's a list of names of polygons in the Dr. Math FAQ. Look for 
"Naming polygons" at:

  http://mathforum.org/dr.math/faq/   

-Doctor Tom,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/   


Date: 9/16/96 at 9:36:42
From: Dee Sypherd
Subject: Re: 7, 9 Sided Polygons

Dear Dr. Math,

Thank you for your help with polygons.  We have another question 
regarding the prefix "sept".  If "septi" means seven, why is September 
the 9th month of the year?

Thanks,
Mrs. Sypherd's Class  (4th - 6th Grades)
Ayr Public School
Ayr, NE


Date: 9/16/96 at 14:6:4
From: Doctor Tom
Subject: Re: 7, 9 Sided Polygons

And "Oct"ober means 8 and "Nov"ember 9 and "Dec"ember 10.  There used
to be only 10 months, but 2 were added later.  But rather than change
the names, the two months were simply stuffed in.  I've forgotten
the exact history of this, but I remember reading a great description
of this by Isaac Asimov in one of his books.  The history of the
calendar is fascinating.

The main problem was a desire to synchronize "months" with the
moon's motion, and that actually has little to do with the motion
of the earth around the sun.

-Doctor Tom,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/   
    
Associated Topics:
Elementary Calendars/Dates/Time
Elementary Triangles and Other Polygons
Elementary Two-Dimensional Geometry

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