Pyramid edges
A level mathematics syllabus 2020 zimsec
The most distinct edges on the pyramid, those on the sunlit side, were marked by visual averaging. These edges were extended to locate the position of the hypothetical original apex. A straight line was drawn from the apex through the flat protuberance at the front of the pyramid to mark what appears to be an axis of symmetry.
All lateral edges of a regular pyramid are equal; all lateral faces are equal isosceles triangles. A height of lateral face (SF) is called an apothem of a regular pyramid.