6th Grade Math Textbook, Progress

Solid Figures

10-17

parallel congruent bases

lateral face (a polygon; a face that is not a base) edge (a segment) vertex (a point)

The model at the right is an example of a solid figure. Solid figures are three-dimensional. Their parts are not all contained in the same plane.

Solid figures formed by flatplane surfaces are called polyhedra.

Polyhedra are named by the shape of their base.

Prisms: polyhedra having polygons as parallel congruent bases joined by rectangular faces.

triangular prism rectangular prism pentagonal prism

Pyramids: polyhedra having one polygon as a base and triangular faces that share a common vertex.

triangular pyramid rectangular pyramid hexagonal pyramid

Not polyhedra: solid figures having curved surfaces.

cylinder cone sphere

Is the figure a prism or a pyramid? Tell how many faces, edges, and vertices it has. (Hint: The bases are also faces.)

one base

8206-2_362-363 10/12/07 6:49 PM Page 362