Associated Topics || Dr. Math Home || Search Dr. Math

### Quadrilateral Classification: Definition of a Trapezoid

```
Date: 01/15/97 at 13:45:54
From: Anonymous
Subject: Trapezoid ?

Dr. Math,

What is the correct definition for a trapezoid?  And why?

My questions come from the Math Department at Carroll Middle School
in SouthLake, Texas.  Two of the math teachers have found well-known
publications with very different definitions for a Trapezoid.

1) Trapezoid: Quadrilateral with at least 1 pair of sides parallel.

2) Trapezoid: A trapezoid is a quadrilateral with exactly one pair of
parallel sides.

Can you help? Thanks.

- Craig C.
```

```
Date: 01/15/97 at 15:48:19
From: Doctor Steve
Subject: Re: Trapezoid ?

Hello Craig,

This has actually been discussed quite thoroughly by professionals on
our geometry newsgroups. You can search for these discussions by going
to

http://mathforum.org/kb/forum.jspa?forumID=128

and searching for the word  trapezoid . In the list of found
discussions you'll see three that most relate: Definition of a
trapezoid, Classification of Quadilaterals, and Defining

The bottom line is that these professionals are most comfortable with
a definition like the first one you offer.

Here is a classification scheme that reflects the first definition,
found in "A Problem Solving Approach to Mathematics for Elementary
School Teachers" by Billstein et al.

/           \
/               \
Kite                    Trapezoid
|                      /       \
|                    /          \
|              Parallelogram   Isosceles
|              /       \       Trapezoid
|            /           \       /
\          /               \   /
Rhombus                  Rectangle
\                  /
\             /
\        /
Square

taken from article by Tad Watanabe in thread

http://mathforum.org/kb/message.jspa?messageID=1076714

-Doctor Steve,  The Math Forum
Check out our web site!  http://mathforum.org/dr.math/
```
Associated Topics:
Elementary Definitions
Elementary Geometry
Elementary Triangles and Other Polygons
High School Definitions
High School Geometry
High School Triangles and Other Polygons
Middle School Definitions
Middle School Geometry
Middle School Triangles and Other Polygons

Search the Dr. Math Library:

 Find items containing (put spaces between keywords):   Click only once for faster results: [ Choose "whole words" when searching for a word like age.] all keywords, in any order at least one, that exact phrase parts of words whole words

Submit your own question to Dr. Math
Math Forum Home || Math Library || Quick Reference || Math Forum Search