
Re: PARCC Definition of Trapezoid
Posted:
May 2, 2013 11:23 AM


Except there is something called an "isosceles trapezoid" (or isosceles trapeziumdepending on where you live), which is not a parallelogram, because it has line symmetry.
Either way you think of a trapezoid, it's a question of arbitrary definition, not mathematical principle, which is why we think the inclusion of something so low level as a testable element of Common Core (a trapezoid is first mentioned in 1st gradewill they test that?) is just another of an endless series of dumbed down standards.
Using one definition over the other is also not being honest to students, a practice we abhor.
Sorry to those educators who have to spend time worrying about such issues, which could be time spent on bona fide mathematical questions instead.
Here's a question that involves a trapezoid that doesn't care less what the definition is: http://fivetriangles.blogspot.com/2013/04/65papercuts.html

