Projection of Apex of Right Pyramid

Definition of a right Pyramid : The slant height of all edges are equal. This demonstration would like to show that the projection of Apex of a right Pyramid would be coincided with the circumcentre of the base of the pyramid.
1. Ask students how to find the projection (V') of the Apex (V) of the pyramid. ( After discussion, please tick "projection" to show it.) 2. Ask students which centres of triangle ABC would coincided with V' ( After discussion, please tick "4 center" to show it.)