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Topic: Based on the quadrilateral tree
Replies: 14   Last Post: May 8, 2013 7:00 PM

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Gary Tupper

Posts: 544
Registered: 12/3/04
Re: Based on the quadrilateral tree
Posted: May 2, 2013 8:01 PM
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On 5/2/2013 1:48 PM, Wayne Bishop wrote:
> But he is also right. Although favored in some circles, it is one of
> those (rather few) situations where the inclusive definition is not
> universal. In fact, I think the majority of us prefer his, exactly 1
> pair of parallel sides. Moreover, convictions border on the
> religious. You know, God is on our side whichever side that is.
> Wayne

I'm not sure how God fits in here, but:

if we define a trapezoid to be a quadrilateral with 2 (or more) parallel
sides, then any property of a trapezoid will cascade down to
parallograms, rectangles, squares & rhombi. The only such property I am
aware of: the area of a trapezoid is the product of the distance between
parallel sides, and the average length of the parallel sides. And this
formula does indeed cascade down - even to a triangle if we view it as a
degenerate with side length 0 at the vertex.

If there is a comparable advantage to using the restrictive definition,
I do not know it.

Gary Tupper
Terrace BC

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