Subject: [Fwd: Geometry Question]
From: RWW Taylor (rwwt@mac.com)
Date: Tue Apr 11 2000 - 09:20:08 EDT
attached mail follows:
John R Gann writes:
> Anyone know of a way to estimate the volume and surface area of:
>
> 1) a right-circular cone
> 2) a pyramid
>
> I'm trying to do some investigations with my class without resorting to
> looking up formulas in a text book. Thanks if you can help.
Cones and pyramids (and also cylinders, prisms and antiprisms) are
_developable_ surfaces -- the surface area can be laid out in a plane. If you
are using actual physical models (even models built from paper and tape) the
models can be rolled and mapped by students to get a "feel" for where the
surface area lies (in the base, or from the sides). Going the other way, if you
are working from a described solid, actually building a model with paper and
tape is an excellent way to develop a feeling for the amount of material
required for the sides. If the model built is relatively "tight", you can then
go on to estimate the volume by filling the interior with some substance (e.g.
cornmeal) that you can empty and measure with a measuring cup.
RWW Taylor
National Technical Institute for the Deaf
Rochester Institute of Technology
Rochester NY 14623
>>>> The plural of mongoose begins with p. <<<<
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