# David Chandler

## Welcome to the SchoolhouseTeachers.com High School Math Lessons

#### Introduction to Graphing Using GeoGebra

Graphing is extremely important in mathematics. Many find it more interesting than working with equations directly because it is so visual. It is where algebra and geometry come together. Lines and curves, which are geometric objects, correspond to equations, which are algebraic objects.

Learning graphing from a textbook is a little awkward because images in textbooks are static. A tool like GeoGebra makes graphing come alive. Once you get a feel for the equations of lines and curves with a dynamic tool like this, the concepts taught in textbooks should make more sense.

The first requirement for this month is to download and install GeoGebra— http://www.geogebra.org/cms/. The first of the series of videos (there are six this month) walks you through this process.

The problem set is correlated with the videos, so watch each one and do the exercises before going on to the next video.

## Go to Graphing/GeoGebra Lesson Page.

Have fun!

*David Chandler*

* * * * *

I hope you are enjoying these monthly explorations in mathematics as much as I am enjoying developing them.

Here are the sources for the free tools from the Internet we have used throughout these lessons. You may need these for various projects in my lessons:

Libre Office http://www.libreoffice.org/ Or, Open Office http://www.openoffice.org/ Geogebra http://www.geogebra.org

Commercial substitutes, such as Excel and The Geometer’s Sketchpad, can also be used.

*David*

## Review David Chandler’s Lesson on Finding Areas Using Reasoning.

## Review David’s Lesson on the Pythagorean Theorem.

**Review David’s Lesson on Finding Areas Without Formulas.**

## Review David’s Lesson on Pi.

**David Chandler** is author of the Home Study Companion series. David loves to teach mathematics! He has a BS from Harvey Mudd College (independent major combining physics and engineering), an MA in Education from Claremont Graduate University, and an MS in Mathematics from Cal Poly University.

*David has taught physics, mathematics, astronomy, and computer programming in public, private, international, and charter schools and community colleges since the early 1970s. He currently teaches at Eleanor Roosevelt Community Learning Center, a K-12 charter school that works with homeschooling families. Working with homeschoolers has led David to see the need for supplementary materials like his Math Without Borders program.*

*One of his more interesting projects at his school is designing a mixed grade level course called Math Explorations (for 2nd grade through Junior High). Math Explorations involves “precursor activities” that don’t necessarily look like mathematics. His students do puzzles, mazes, perspective drawing, distorted photographs, and a lot of other fun and fascinating stuff. It’s not about math skills, per se. It’s about how the brain is wired! David says: “This is the kind of thing I can do at a charter school working with homeschoolers that I couldn’t possibly get away with in a standard public school.”*