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Topic: Question about trapezoids
Replies: 7   Last Post: Jul 8, 2008 5:13 AM

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Ed Wall

Posts: 845
Registered: 12/3/04
Re: Question about trapezoids
Posted: Dec 13, 2006 5:45 PM
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This is sort of what is being said below: Okay, draw your isosceles
triangle. Chose a length a little longer than the base and using, for
example, B as a center draw a circle intersecting AC at two points.
Label E the one nearer to C. Taking C as a center and using the same
length do the same for BA; however, label D the one nearer to A. Now
DC and BE are certainly equal, but is BCED an isosceles trapezoid (I
notice you are talking about BCDE so perhaps I misunderstand)?

Ed Wall

>The problem seems to come down to special cases of SSA.
>When you speak about 'diagonals' there is am implication that these
>are longer than the missing third side, and that the 'diagonals'
>cross while the missing third sides do not cross.
> If this is true, then you are in a subcase where SSA gives the
>necessary congruence.
>Walter Whiteley
>On 13-Dec-06, at 1:33 PM, Jason Fahy wrote:
>Poor phrasing up there, let me try again:
>Is it true that IF a quadrilateral has two equal base angles and
>diagonals of equal length, it must be an isosceles trapezoid? If
>so, etc, etc...

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