Question 1200707
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Hello,


your pie is a right cylinder,  and your piece of the pie is called in  Geometry  " a sector of a right cylinder ".


See the images at this link

https://www.google.com/search?q=sector+of+a+cylinder+image&rlz=1C1CHBF_enUS910US910&oq=sector+of+a+cylinder+image&aqs=chrome..69i57j33i160.12078j0j15&sourceid=chrome&ie=UTF-8 



For such geometry object,  the terms  " side "  is  INAPPLICABLE.  The relevant term is the  " radius ".


The term  " curve "  is not applicable,  too.  The relevant term is  " the arc of the circle at the base ".


If you want to tell about the length of this  " curve ",  you should say  " the length of the arc at the base ".



Learn the terminology and use it properly - otherwise, the people around will not understand you.



On cylindrical solids,  you may read and learn from these lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Volume/_Volume-of-cylinders.lesson>Volume of cylinders</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/geometry/Solved-problems-on-volume-of-cylinders.lesson>Solved problems on volume of cylinders</A>

in this site &nbsp;(at no charge and without registration).



You will find there the links to lessons on other Geometric solids, too.



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