Geometry: Putting Quadrilaterals in the Forefront

Putting Quadrilaterals in the Forefront

If you look around your house, the most common polygon you will see is a quadrilateral. Your walls, windows, doors, floors, and ceilings are probably quadrilaterals. There must be something special about them if these four-sided polygons form the basis for most of our building designs.

There are many different quadrilaterals. Squares and rectangles are probably the most popular, but many people appreciate kites, parallelograms, rhombuses, and trapezoids. Each of these quadrilaterals has its own peculiar combination of properties that warrant giving it its own special name.

Before you started reading this, I'm sure you could pick out a square in a quadrilateral line-up. But you've probably never written a theorem (the mathematical equivalent of a poem) about a square. That's all about to change.

Excerpted from The Complete Idiot's Guide to Geometry © 2004 by Denise Szecsei, Ph.D.. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.

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