I’ve embedded a web version of Geogebra (a free, cross-platform, geometry and algebra tool) below. It will take a little bit to load, and will only work in a web browser, but it is an easy way to test out Geogebra without installing it.

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)