BASIC CONCEPTS OF POLYHEDRONS
This module will introduce to you basic ideas about polyhedrons. It will help you determine the surface of polyhedrons. It will also explain to you regular polyhedrons, its classifications and how to construct it.
Learning Goal
This module is written for you to:
1. Define polyhedrons;
2. Identify and illustrate the surface of polyhedrons;
3. Determine convex polyhedrons;
4. Determine regular polyhedrons; and
5. Construct regular polyhedrons.
Let’s do some warm-up
1. What is another name for a corner or a point? _______________
2. The prefix”poly” means _____________.
3. What is another name for cube? _________________
4. How many regular polyhedrons are there? ___________________
Let’s read and understand
Lesson 1
Polyhedrons
A polyhedron (plural polyhedrons or polyhedra) is a three-dimensional geometric solid whose boundary consists of plane polygons. In Greek, poly means “many” and hedron means “face”.
The polygons which bound the polyhedron are its faces; the sides of these faces are the edges and their vertices are the vertices of the polyhedron. The faces, edges, and vertices taken together form the surface of the polyhedron.
Examples:
For polyhedrons below, tell the number of vertices, edges, and faces. Also determine the geometric name of the faces. 1.
Answer:
The figure is made up of five triangles and one pentagon so there are six faces. There are six vertices--one on the "top" and five on the "bottom." There are ten edges--five on the "sides," and five on the "bottom."
2.
Answer:
The figure is made up of three triangles only so there are three faces. There are four vertices--one on the "top" and three on the "bottom." There are six edges--three on the "sides," and three on the "bottom."
Let’s have some drill
For polyhedrons below, tell the number of vertices, edges, and faces. Also
References: H. E. SLAUGHT AND N. J. LENNES, The Project Gutenberg EBook of Solid Geometry with Problems and Applications (Revised edition), Release Date: August 26, 2009 [EBook #29807] WILLIAM JAMES RALPH, Microsoft ® Encarta ® 2009