Friday, January 18, 2013

Some rectangles are squares!

I am pitching a fit. So far I have raised my voice, stomped my feet, and thrown a pencil. A more sensitive child might be alarmed, but the strapping six-foot athlete beside me looks more bemused than upset.  [Note: This fit was entirely for effect. A more sensitive child would never have seen it.] And what has brought on this display of temper?  Yet another high school geometry student has mis-defined a rectangle as having “two long sides and two short sides.”

I have spent countless hours trying to beat that notion out of the heads of my high school students and replace it with the correct definition: A rectangle is a quadrilateral with four right ANGLES. It’s all about the angles. The lengths of the sides are immaterial. In fact the sides could all be of equal length. That’s right. Just as a cardinal is a particular type of bird, a square is a particular type of rectangle.

Recently I have decided that it might be better to focus my attention on the other end of the problem: picture books.  Ideally, students would never learn the incorrect definition in the first place, and it seems that if picture books got it right, that would be a step in the right direction.

My experience so far with picture book publishers is that as long as the book is popular, they don’t care if it contains errors. Therefore we need to hit this on two fronts: First, make sure that the publishers get enough complaint letters that they begin to wonder whether or not a correct book would be more popular, and second reduce the popularity of incorrect books by giving them bad reviews. 

Below, you will find three books that should be permanently out of print along with contact information for the publisher.  The book name itself is a link to the Amazon page for that book in case you wish to write a negative review. In addition, pass this information on to other parents, make letter-writing an assignment for your geometry class, and alert the media! Leave a comment if you get a response. Let’s see if we can get this straightened out once and for all.

Quote to reference, page 15:  "A rectangle is a shape that has four right angles and four sides. Opposite sides are parallel and have the same length.  The perpendicular sides are a different length."

Circus Shapes - published by Harper Collinsto send them an email
Quote to reference, pages 24, 25:  "The bears form a rectangle. - two sides short and two sides long." 

When a Line Bends...A Shape Begins - published by Houghton Mifflin - to send them an email
Quote to reference:  "A rectangle is like a square with something rearranged. Two sides are long and two are short. The four sides now are changed."  In addition, this book goes on to say that if you rotate a square 45 degrees it becomes a "diamond."

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