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Topic: trapezoid clarification
Replies: 55   Last Post: Apr 24, 2017 2:30 PM

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 Roberta M. Eisenberg Posts: 269 Registered: 10/9/09
Re: trapezoid clarification
Posted: Jun 3, 2014 10:47 PM
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The property that you mention is a thm that follows from the def of isos trap using the exclusive defn. (An isos trap is a trap whose non-// sides are congruent.)

NYS must supply teachers and students with a complete list of definitions and not only the one inclusive def. of trap. How do they define isos trap with the inclusive def of trap? And what thms about isos traps follow from whatever def is supplied to us?

Someone supplied a def of isos trap about a week ago, but does NYS accept that?

Bobbi

On Jun 3, 2014, at 9:31 PM, Elaine Zseller <EZseller@nasboces.org> wrote:

> All rhombuses are not isosceles trapezoids. Isosceles trapezoids have their base angles congruent. Only the rhombus known as a square fits that definition.
>
> From: owner-nyshsmath@mathforum.org [mailto:owner-nyshsmath@mathforum.org] On Behalf Ofbcwaldner@aol.com
> Sent: Wednesday, May 28, 2014 5:52 AM
> To: nyshsmath@mathforum.org
> Subject: Re: trapezoid clarification
>
> Grace
> Of course you are right and your summary of trapezoid clarifications are going to be helpful to anyone who was not sure about the implications of this revised definition. Good point of how it can be used in a proof.
> Bruce
>
> Sent from AOL Mobile Mail
>
>
> -----Original Message-----
> From: Grace Wilkie <gwilkie@highlands.com>
> To: nyshsmath <nyshsmath@mathforum.org>
> Sent: Tue, May 27, 2014 10:33 PM
> Subject: Re: trapezoid clarification
>
>
> Inclusive, exclusive, reclusive ... hopefully there will be no questions either test ... you can't have one definition for the common core test and another definition for the regents test ... look at all the discussion we are having ... and there are plenty of teachers that don't even realize there is a different definition ... and we still have not fine tuned the isosceles trapezoid ...
>
> Here is what I get - but of course I could be wrong
>
> All parallelograms, rectangles, rhombuses and squares are trapezoids. Some trapezoids are parallelograms, rectangles, rhombuses and squares.
>
> All rectangles, rhombuses and squares are isosceles trapezoids. Some isosceles trapezoids are rectangles, rhombuses and squares.
>
> Proofs can now include the word 'trapezoid' ie. A rhombus is an isosceles trapezoid with the diagonals perpendicular to each other.
>
> I wish the state would come out with the conversion score key before the regents but I know that should happen but will not. I wish all parts of these tests were open to the public - we need to work on SED to make that happen ... if we expect to 1. help students then we need to know what they got wrong - not a topic but the question and the student response 2. help teachers improve instruction then we need to be informed what our students understood and did not understand 3. have faith that the tests are valid and reliable - we will never know if there are errors if we don't see them (there have been mistakes in the past).
>
> I will have good thoughts for the students and teachers going through the common core test and possibly the regents.
>
> As always,
> Grace Wilkie
>
>
> On Tue, May 27, 2014 at 10:36 AM, Elaine Zseller <EZseller@nasboces.org> wrote:
> The inclusive definition of trapezoid would classify rectangles and squares as isosceles trapezoids. An Isosceles trapezoid has congruent base angles and at least one pair of parallel sides. Rectangles and squares fit these more restrictive criteria. All parallelograms are trapezoids but all parallelograms do not fit the more restrictive criteria of an isosceles trapezoid.
>
> - -----Original Message-----
> From: owner-nyshsmath@mathforum.org [mailto:owner-nyshsmath@mathforum.org] On Behalf Of Jennifer Sauer
> Sent: Sunday, May 25, 2014 9:38 PM
> To: nyshsmath@mathforum.org
> Subject: Re: trapezoid clarification
>
> According to the website below, when using the inclusive definition of a trapezoid, an isosceles trapeziod is still defined as a "strict" trapezoid (exclusive definition) with congruent legs. Therefore squares and rectangles would not be included. Does that agree with the CCSS definition?
>
> http://www.math.washington.edu/~king/coursedir/m444a00/syl/class/trapezoids/Trapezoids.html
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