Centroid of a Triangle

This applet shows the construction of the centroid in a triangle.
Move points A, B and C. Make different triangles and notice what happens to point G. 1. What are the dashed lines in the construction called? 2. How are those dashed lines constructed? 3. What is point G called? 4. Is it possible for point G to be located outside of the triangle? 5. What special property do you think point G has with the triangle?