


Description 



Crosssection: The region formed by the intersection of a solid and a plane. 
Cross Section
Below are three cross sections of a pyramid with
a square base:

If the pyramid is cut with a plane (green) parallel to the
base, the intersection of the pyramid and the plane is a square cross section
(red).


If the pyramid is cut with a plane (green) passing through the
top vertex and perpendicular to the base, the intersection of the pyramid and
the plane is a triangular cross section (red). 

If the pyramid is cut with a plane (green) perpendicular to the
base, but not through the top vertex, the intersection of the pyramid and the
plane is a trapezoidal cross section (red).



