## Wednesday, August 31, 2011

### Napoleon's Theorem

1. Move points A, B, and C and observe what happens.
2. Make a conjecture about your observation.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)

If equilateral triangles are placed on the sides of any triangle as shown above (all inward or all outward), the centers of those equilateral triangles themselves form an equilateral triangle. This is known as Napoleon's theorem.

## Saturday, August 27, 2011

### GeoGebra 4.0 release candidate and GeoGebra 4.2

The GeoGebra 4.0 Release Candidate is now online. Here is the announcement of the GeoGebra Team about it.
According to the team, the GeoGebra 4.0 offline installers will be released in a few weeks. You can also now explore the new GeoGebra 4.2 Beta.

## Thursday, August 25, 2011

### Midpoint of a segment

Drag the slider to construct (compass and straightedge) the midpoint of segment AB.

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I will create a tutorial about this in Mathematics and Multimedia.

## Wednesday, August 24, 2011

### Thales' Theorem

The Thales' Theorem states that if ABC are points on the circle, and AB is a diameter, then angle ACB is a right angle.

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The Proof of this theorem is very easy, so I left this as an exercise to students.

## Monday, August 15, 2011

### Random Graph

An applet that generates a random linear graph with integer slope and y-intercept. The command button should be showing up with label New Graph, but I supposed that the beta version is still 'buggy.'

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

## Friday, August 12, 2011

### Embedding GeoGebra Applets in Wordpress

I created this blog to accommodate the GeoGebra applets I used in Mathematics and Multimedia. Math and Multimedia was created using Wordpress.com and was later migrated to a hosted Wordpress blog. Despite the transfer, I still had difficulty in embedding GeoGebra applets until recently Micky Bullock wrote a tutorial about it.

My colleague, Erlina Ronda of Mathematics for Teaching, one of the contributors of this blog, discovered another way. I have written a tutorial about her discovery here.

Math and Multimedia houses more than 50 GeoGebra step by step tutorials, the most current of which is the GeoGebra 4.0 sneak peek series

## Tuesday, August 9, 2011

### Simson's Line

The Simpson line is the line containing points C, D, E, the feet of the perpendiculars from point P on the circumircle of triangle RST to the sides (or their extension) of  the triangle.

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The theorem was named after Sottish mathematician Robert Simson

## Saturday, August 6, 2011

### The Riemann Sum

Drag the circle in slider n to investigate the sum of the area of the rectangles.

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Make a conjecture about the relationship between the area sum of all the rectangles and the total area under the curve.

## Tuesday, August 2, 2011

### Origami Square Root Improved

This is the improved version of my previous origami and mathematics post. There is a discussion about this applet here.

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To those who want to learn how to blog, you may want to check our my new blog at Blogineering.com.