The base of a regular quadrilateral pyramid π is a square with side length 2a and its lateral edge has length a17. Let M be a point inside the pyramid. Consider the five pyramids which are similar to π , whose top vertex is at M and whose bases lie in the planes of the faces of π . Show that the sum of the surface areas of these five pyramids is greater or equal to one fifth the surface of π , and find for which M equality holds. inequalitiessolid geometrypyramidgeometry3D geometry