## 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.

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 here» Read more

## 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.

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). » Read more

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