Cross-sections are one way that two-dimensional objects are connected to three-dimensional objects.

Explore connections between a 2-dimensional net and a 3-dimensional box. Later in this section, use equations with variables to solve real world problems that use 2 and 3-dimensional objects.

This lesson focuses on polyhedra; a polyhedron (the plural is polyhedra) is a 3-dimensional solid object that is made up of polygons. Euler's Polyhedron Formula: In every polyhedron, the number of faces (F) plus the number of vertices...