The two-dimensional diagonal cross section of a hexagonal pyramid is a triangle. To understand why, let’s consider the structure of the pyramid itself.
A hexagonal pyramid consists of a hexagonal base and six triangular faces that converge at a single apex point above the center of the base. When we take a diagonal cross section through the pyramid, we are essentially slicing it diagonally, which intersects both the apex and two non-adjacent vertices of the hexagonal base.
This diagonal cut will form a triangular shape, as the line segment connecting the points on the base will create one side of the triangle, while the two segments connecting these points to the apex form the other two sides. Therefore, the result of this diagonal cross section through a hexagonal pyramid is a triangular shape.