This shows the construction of some of the classic triangle centres (Circumcentre, Incentre, Centroid, Orthocentre) and explains their properties.
It show's that the Orthocentre, the Centroid and the Circumcentre lie on the Euler line, and how they are positioned.
It show's how the ninepoint circle is constructed and explains its properties.
It shows the excircles, and demonstrates that the ninepoint circle is tangent to these and the incircles.
Checkboxes allow the user to show only the basic constructions required for each of the demonstrations, or to superimpose further detail as required.
