Classifying 3D shapes

In this lesson, we will learn:

• That 3D shapes are shapes with 3 dimensions
• The properties/attributes of 3D shape (face, vertex, edge) and how to count them
• The different types of 3D shapes: prism shapes, pyramid shapes, and curved surface shapes
• All the subtypes of 3D shapes:
• triangular prism, rectangular prism, cube, pentagonal prism, hexagonal prism
• triangular pyramid, rectangular pyramid, square pyramid, pentagonal pyramid, hexagonal pyramid
• cylinder, cone, sphere

Notes:

• 3-dimensional shapes (3D shapes) are also called “solid figures” or “space figures”
• 1-dimensional (1D) is a straight line, 2-dimensional (2D) is a flat shape, and 3-dimensional (3D) is a solid figure like a cube in real life.
• Recall that dimensions are different planes or directions of measurement


• There are three properties for 3D shapes:
$\qquad \qquad$1. Faces
$\qquad \qquad$2. Edges
$\qquad \qquad$3. Vertices (singular: vertex)
• Faces are sides; the flat outer surfaces enclosed by lines
• Edges are lines where faces meet; touching sides
• Vertices are corners; two or more edges meet/converge at a vertex

There are three types for 3D shapes:

$\qquad \qquad$1. Prisms
$\qquad \qquad$2. Pyramids
$\qquad \qquad$3. Curved surface shapes

Prisms are 3D shapes made by extending a polygon base (shapes with straight edges only)

• All other faces, besides the base, are rectangles
• All prisms have at least 2 pairs of parallel faces
• A cube is a special prism (rectangular prism) where all edges are the exact same length (all faces are squares)

• Pyramids are 3D shapes with only one base
• All other faces, besides the base, are triangles
• All the triangle faces converge and connect at a top point (common vertex)

• Curved surface shapes are 3D shapes with curved surfaces
• These shapes usually have a circle shape as the base
• A cylinder is not a “circular prism” because prisms are made out of extending polygons only (a circle is not a polygon)

• There are special formulas which show the rules between the number of sides in the base shape and the number of faces (f) /vertices (Ve) /edges (E) for a 3D shape: