Find the centroid.
This applet is done from teacher Josep Lluís Cañadilla (http://www.geogebratube.org/user/profile/id/1324) using JavaScript methods. Original one (not translated) is available at http://www.geogebratube.org/student/m11785
In a step by step guided activity, GeoGebra sends back a grade and error-messages for the student learning process.
