
Re: trapezoid clarification
Posted:
Jun 3, 2014 10:57 PM



"Isosceles" means "equal legs"  If a trapezoid has exactly one pair of parallel sides, then an "isosceles trapezoid" has the nonparallel 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:* ownernyshsmath@mathforum.org [mailto: > ownernyshsmath@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: ownernyshsmath@mathforum.org [mailto: ownernyshsmath@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 > * > * Read prior posts and download attachments from the web archives at > * http://mathforum.org/kb/forum.jspa?forumID=671 > ******************************************************************* > ******************************************************************* > * To unsubscribe from this mailing list, email the message > * "unsubscribe nyshsmath" to majordomo@mathforum.org > * > * Read prior posts and download attachments from the web archives at > * http://mathforum.org/kb/forum.jspa?forumID=671 > ******************************************************************* > > >

