# Review: Dr. Geo

By Murray Bourne, 31 Jul 2013

Dr. Geo is free stand-alone math software that allows you to "design & manipulate interactive geometric sketches with constraints."

Using Dr. Geo you can create points, join them with lines, construct parallels, perpendiculars, bisectors, circles, arcs and polygons. You can perform transformations like reflections and translations, you can measure the length of objects and there's also the possibility of animating objects. Scripting is also possible and there is the facility to build and execute macros.

So Dr. Geo is similar in many ways to that other free offering, GeoGebra (see my tutorial review), but it appears to be more versatile in terms of platforms. (GeoGebra is java-based, so up to now it has not played so well on mobile devices. However, an iPad version of GeoGebra is under development as I write.)

Dr Geo is quite platform-agnostic, with PC, Mac and GNU-Linux versions. There are iPad and Android versions and there's even the option to install it on Sugar XO OLPC (One Laptop Per Child).

See Videos and Tutorials showing what you can do with Dr Geo.

There are many constructions included in the download and these are a good starting point for your own constructions.

Below are some screen shots of Dr. Geo in action.

The first one shows an aspect of the interface that I like - the controller wheels on the right and bottom of the working area which operate the zoom (the top right controller), or moving the construction up or down (the bottom right controller) or moving the object left-right (bottom controller). These are quite intuitive and work well (although it is a bit too easy to zoom way too quickly and your object disappears. This may be a problem for younger users.)

In the screen shot you can also see the helpful instructions given at the bottom of the screen. These tips change as you attempt to perform different constructions.

The number on the segment is its length and I'm animating a point on the arc.

The following screen shots are found on the Dr. Geo site:

## The iPad Version

It was a bit tricky to find the iPad version on the App Store, since it is listed as "Dr Geometry", not Dr. Geo. (A search on "Dr Geo" brings up "no results".)

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