Let's Face It
Geometry
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Objective
Students will be able to identify the five regular polyhedra (tetrahedron, hexahedron,
octahedron, dodecahedron and icosahedron) and describe basic characteristics about each.
Overview of the Lesson
Students are introduced to the idea of threedimensional figures by first reviewing
polygons and regular tessellations. Comparisons are made between regular tessellations
and five special polyhedra. These polyhedra, known as the Platonic Solids are the
tetrahedron, hexahedron, octahedron, dodecahedron and the icosahedron. Students are
provided with the necessary materials to construct these shapes. However, they must
decide how to build them on their own. Using nets as blueprints, students construct the
polyhedra and record the number of faces, edges and vertices for each. Finally, they are
asked to look for a relationship between the number of faces, edges and vertices, (Euler’s
formula).
