Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

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

 Messages: [ Previous | Next ]
 Jonathan Halabi Posts: 119 Registered: 8/16/08
Re: trapezoid clarification
Posted: Jun 3, 2014 10:57 PM
 att1.html (8.7 K)

"Isosceles" means "equal legs" -
If a trapezoid has exactly one pair of parallel sides, then an "isosceles
trapezoid" has the non-parallel bases equal. As a consequence, base angles
are equal.

"Base angles are equal" is a consequence of using a particular definition
of a trapezoid. NY State is no longer using that definition.

Jonathan Halabi
the Bronx

On Tue, 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 Of *bcwaldner@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
> *******************************************************************
> * To unsubscribe from this mailing list, email the message
> * "unsubscribe nyshsmath" to majordomo@mathforum.org
> *
> * http://mathforum.org/kb/forum.jspa?forumID=671
> *******************************************************************
> *******************************************************************
> * To unsubscribe from this mailing list, email the message
> * "unsubscribe nyshsmath" to majordomo@mathforum.org
> *