The Euler Line (Geogebra)

The diagram below contains a triangle $\Delta ABC$ with circumcentre $O$, centroid $G$ and orthocentre $H$. Euler's theorem says that $O,G$ and $H$ are collinear. 

You can see this in the diagram below, the Euler line through the points $O,G$ and $H$ is coloured in black, and its extension is coloured in orange.

By moving the vertices $A$, $B$ and $C$ you can see how the Euler line depends on these points.

See here.