1-7 Three-Dimensional 1-7 Three-Dimensional FiguresFigures

What is a polyhedron?What is a polyhedron?

How are polyhedrons classified?How are polyhedrons classified?

What are Platonic solids?What are Platonic solids?

You identified and named two-dimensional figures.

• Identify and name three-dimensional figures.

DefinitionsDefinitionsA A polyhedronpolyhedron is a solid with all flat surfaces is a solid with all flat surfaces

that enclose a single region of space.that enclose a single region of space.

A A faceface is each flat surface of the polygon is each flat surface of the polygon

Faces are named in the same way as polygons.Faces are named in the same way as polygons.

EdgesEdges are the line segments where the faces are the line segments where the faces intersect.intersect.

A A vertexvertex is the point where three or more edges is the point where three or more edges meet.meet.

Polyhedrons or polyhedra are named by the Polyhedrons or polyhedra are named by the shape of their bases and type of solid.shape of their bases and type of solid.

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Prisms and pyramids are Prisms and pyramids are Polyhedrons.Polyhedrons. Cylinders, cones and spheres are not.Cylinders, cones and spheres are not.

BasesBases

The bases of the figure are the two The bases of the figure are the two parallel congruent faces of the three parallel congruent faces of the three dimensional figure.dimensional figure.

BEWARE!! BEWARE!! The figure may not be sitting on its baseThe figure may not be sitting on its base

Naming polyhedronsNaming polyhedrons

Polyhedrons are named by the shape of Polyhedrons are named by the shape of their bases.their bases.

Identify SolidsIdentify SolidsDetermine whether the solid is a polyhedron. Then identify the solid. If it is a polyhedron, name the bases, faces, edges, and vertices.

The solid is formed by polygonal faces, so it is a polyhedron. The bases are rectangles. This solid is a rectangular prism.

Answer: rectangular prismBases: rectangles EFHG, ABDC Faces: rectangles FBDH, EACG,

GCDH,EFBA, EFHG, ABDCVertices: A, B, C, D, E, F, G, H

Identify SolidsIdentify SolidsDetermine whether the solid is a polyhedron. Then identify the solid. If it is a polyhedron, name the bases, faces, edges, and vertices.

The solid has a curved surface, so it is not a polyhedron. The base is a circle and there is one vertex. So, it is a cone.

Answer: Base: circle TVertex: Wno faces or edges

Identify the solidIdentify the solid

A. triangular prism

B. triangular pyramid

C. rectangular pyramid

D. cone

Platonic SolidsPlatonic Solids

Identify the solidIdentify the solid

A. cone

B. cylinder

C. pyramid

D. polyhedron

Identify the solidIdentify the solid

A. triangular pyramid

B. pentagonal prism

C. rectangular prism

D. square pyramid

What is a polyhedron?What is a polyhedron?A polyhedron is a solid whose faces are A polyhedron is a solid whose faces are

polygons.polygons. How are polyhedrons classified?How are polyhedrons classified?Polyhedrons are named by the shape of their Polyhedrons are named by the shape of their

bases.bases.

Assignment 1-7Assignment 1-7

Page 70, 1, 2, 6-16, skip 12Page 70, 1, 2, 6-16, skip 12