Ryan - Geometry Essentials For Dummies

Geometry Essentials For Dummies

Published by: John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, www.wiley.com

Copyright 2019 by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Control Number: 2019937506

ISBN 978-1-119-59044-6 (pbk); ISBN 978-1-119-59047-7 (ebk); ISBN 978-1-119-59046-0 (ebk)

1. Chapter 6

1. Chapter 1
2. Chapter 2
3. Chapter 3
4. Chapter 4
5. Chapter 5
6. Chapter 6
7. Chapter 7
8. Chapter 8
9. Chapter 9
10. Chapter 10
11. Chapter 11

Geometry is a subject full of mathematical richness and beauty. The ancient Greeks were into it big time, and its been a mainstay in secondary education for centuries. Today, no education is complete without at least some familiarity with the fundamental principles of geometry.

But geometry is also a subject that bewilders many students because its so unlike the math that theyve done before. Geometry requires you to use deductive logic in formal proofs. This process involves a special type of verbal and mathematical reasoning thats new to many students. The subject also involves working with two- and three-dimensional shapes. The spatial reasoning required for this is another thing that makes geometry different and challenging.

Geometry Essentials For Dummies can be a big help to you if youve hit the geometry wall. Or if youre a first-time student of geometry, it can prevent you from hitting the wall in the first place. When the world of geometry opens up to you and things start to click, you may come to really appreciate this topic, which has fascinated people for millennia.

Geometry Essentials For Dummies covers all the principles and formulas you need to analyze two- and three-dimensional shapes, and it gives you the skills and strategies you need to write geometry proofs.

My approach throughout is to explain geometry in plain English with a minimum of technical jargon. Plain English suffices for geometry because its principles, for the most part, are accessible with your common sense. I see no reason to obscure geometry concepts behind a lot of fancy-pants mathematical mumbo-jumbo. I prefer a street-smart approach.

This book, like all For Dummies books, is a reference, not a tutorial. The basic idea is that the chapters stand on their own as much as possible. So you dont have to read this book cover to cover although, of course, you might want to.

Geometry Essentials For Dummies follows certain conventions that keep the text consistent:

• Variables and names of points are in italics.
• Important math terms are often in italics and are defined when necessary. Italics are also sometimes used for emphasis.
• Important terms may be bolded when they appear as keywords within a bulleted list. I also use bold for the instructions in many-step processes.
• As in most geometry books, figures are not necessarily drawn to scale though most of them are.

As I wrote this book, heres what I assumed about you:

• Youre a high school student (or perhaps a junior high student) currently taking a standard high schoollevel geometry course, or
• Youre a parent of a geometry student, and youd like to understand the fundamentals of geometry so you can help your child do his or her homework and prepare for quizzes and tests, or
• Youre anyone who wants to refresh your recollection of the geometry you studied years ago or wants to explore geometry for the first time.
• You remember some basic algebra. The good news is that you need very little algebra for doing geometry but you do need some. In the problems that do involve algebra, I try to lay out all the solutions step by step.

Next to this icon are definitions of geometry terms, explanations of geometry principles, and a few other things you should remember as you work through the book.