3D Solids Vocabulary 6 th Grade Math. Polygon A polygon is a closed figure formed by three or more...

3D Solids Vocabulary

6th Grade Math

Polygon

A polygon is a closed figure formed by three or more line segments.

Examples of Polygons

These Figures ARE NOT Polygons

Why is this figure not a polygon?

It is not made of 3 or more line segments!

Why is this figure not a polygon?

It is not CLOSED!

Face

A face is a flat surface of a

3-dimensional figure.

This is a face. This face is a

polygon.

This is a face. It is circular and

may also be called a base.

Edge

An edge is a line segment where two faces or a face and

lateral surface of a 3-dimensional

figure meet.

Think about this…

Where do we find the edges on a 3-

dimensional figure?

This figure has many edges

…and one

more that we

can’t see!

Does this figure have any edges?

Yes…because the

faces meet the lateral surface.

Face or circular base

Lateral Surface

Vertex (plural – Vertices)

A point…1) Where three or more edges

of a polyhedron meet.2) Opposite the base of a

cone.

This triangular pyramid

has 4 vertices.

Does this cone have a vertex?

Yes! It does have a point opposite

of the face or circular base –

therefore it does have a vertex!

Basebase of a cone – flat circular part,

which may also be called a face

base of a pyramid -polygonal

region that does not intersect

with other faces at the vertex

Bases, cont.bases of a prism –

the two parallel and congruent

regions

bases of a cylinder – the two parallel, circular regions

Cylinder

A cylinder is a 3-dimensional figure with two

parallel, circular bases

or faces.

Cone

A cone is a 3-dimensional figure with

a circular base or face.

PrismA prism is a 3-

dimensional figure with two parallel, congruent bases, and all faces that

are parallelograms (rectangles, etc.).

Naming PrismsPrisms are named

by the shape of their bases (the two sides that are congruent and parallel).

triangular prism

pentagonal prism

Pyramids

A pyramid is a 3-dimensional

figure with one base and

triangular faces.

Naming Pyramids

A pyramid is named by the shape of its base.

triangular pyramid

Definitions adapted from…

•http://intermath.coe.uga.edu•Geometry to Go, published by

Great Source•Teaching Student Centered

Mathematics, Grades 5-8, by John Van de Walle &

LouAnn H. Lovin