Definition of a right Pyramid : The slant height of all edges are equal.[br]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 [br] pyramid. ( After discussion, please tick "projection" to show it.)[br]2. Ask students which centres of triangle ABC would coincided with V'[br] ( After discussion, please tick "4 center" to show it.)