Ed Wall
Posts:
843
Registered:
12/3/04


Re: Question about trapezoids
Posted:
Dec 13, 2006 5:45 PM


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 13Dec06, 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...

