Are vertical and horizontal cross sections of a pyramid? Are they all the same size? Are they all the same shape? Why or why not?

Horizontal cross sections are the same shape: they are all squares if the pyramid is square or rectangles if the pyramid is a rectangle pyramid.

Vertical cross sections are different shape: At the pyramid top they are triangles, at other places they have four sides.

Horizontal cross sections are different size: the more we go to the top of the pyramind, the smaller they get.

Vertical cross sections are different size: the closer we get to the edges, the smaller they become.