Compass and Straightedge Construction Using GeoGebra

In Geometry, the term construction refers to the ‘drawing’ of geometric objects such as lines and circles with only the use of compass and straightedge. Construction does not allow measurement of both lengths and angles. The earliest study of Geometry, particularly parts of Euclid’s Elements focused on “building” Geometry based on compass and straightedge construction. In the following discussion, we will refer to compass and straightedge construction as simply construction.


Compasa and Straightedge

Compass and Straightedge

Using dynamic geometry software (DGS), we can extend construction to computers, tablets, and mobile phones. In this post, we will learn how to use GeoGebra to mimic construction. For those who do not know about GeoGebra yet, it is a free multi-platform mathematics software (not just a DGS) that can be used for teaching and learning mathematics. You may download it here and if you want to learn about it extensively, I have created numerous tutorials on how to use it hereContinue reading

GeoGebra for iPhones is now online

For iPhone users, the long wait is over. In case you missed it (I missed it actually), GeoGebra has released the GeoGebra Graphing Calculator for iPhones last December. I have only personally used the app for a week and I’m really satisfied with its performance and speed on my old iPhone 5.

image via GeoGebra blog

For those who have not tried GeoGebra, it is a free and open-source software for teaching mathematics. We have a lot of tutorials about it here which I’m going to update to the current version of GeoGebra this year.

GeoGebra is available for desktop computers, tablets, and Android phones. It comes on multiple platforms including Windows, Mac, and Linux. You can also install it in the Google Chrome app.

GeoGebra Updates: GeoGebra Exam Mode and Followers Features

There are two recent updates in GeoGebra, the first one is the GeoGebra Exam Mode and the second is the GeoGebra Followers feature for its website users.

GeoGebra Exam Mode

One of the recent developments in GeoGebra is the GeoGebra Exam Mode. In this mode, students can use GeoGebra while taking exams. If a student leaves the the GeoGebra window, the GeoGebra toolbar will turn red (see below) and logs the time and duration the student left the window, so teachers would know if students used other programs.

geogebra exam mode

You can access the GeoGebra exam mode here. It runs in major browsers (Chrome, Firefox, Internet Explorer 11, Safari). It also runs in full screen, so students cannot use any other program while using it. Further, it can be customized allowing access to selected features (e.g. you can disable the CAS window). Continue reading

4 GeoGebra 5 Updates Teachers Will Love

It’s been a while since I have written about GeoGebra, but I have started updating some of the tutorials to GeoGebra 5. For those who have not explored the Archives, I have written numerous GeoGebra tutorials ranging from basics to advanced.

GeoGebra is now version 5.0. New features were added and a lot of improvements had been made. The 3D is now stable and 4 new tools were added. The Insert Image tool now support SVG files. But aside from these, there are simple updates which I really like and I think teachers will also love them. Here are four of them.

1.) Automatic Color Change

Every time you graph a new function in the current version of GeoGebra, it automatically selects a different color. You don’t have to trouble yourself changing the color of the graph of the new functions.  Continue reading

New GeoGebra 3D Now Available for Download

Today, mathematicians, math teachers, math students, and math geeks should celebrate because of this new version of GeoGebra, the GeoGebra 3D. Below is a screenshot of its graphical user interface taken from my own computer. You can how download the new version, read the details about it in the Release Notes, and see some examples.

According to the official GeoGebra blog, the 3d version was headed by Mathieu Blossier (many thanks!) who had been coordinating the project since 2008.
GeoGebra 3D


To learn more about GeoGebra (2d), you can visit the GeoGebra page of this blog which contains more than 50 detailed step by step tutorials on how to use the software.

Enjoy and have fun.

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