The difference between prisms & pyramids. “It’s all about how you slice it!”

Pyramids and prisms are specific kinds of polyhedra Pyramids and prisms are specific kinds of polyhedra. The word polyhedra is the plural form of polyhedron.

A polygon is a 2-dimensional shape.

A polyhedron is a 3-dimensional shape.

The flat surfaces of three-dimensional figures are called faces. Three-dimensional figures are not flat figures. They have length, width, and height. They are also called solid geometric figures. The flat surfaces of three-dimensional figures are called faces. The faces meet at edges. The edges are line segments. The edges meet at vertices (plural of vertex).

Rectangular prism face base edge vertex A rectangular prism has 6 faces, 8 vertices, and 12 edges.

face cube vertex edge A cube, just like a rectangular prism, has 6 faces (all squares), 8 vertices, and 12 edges.

Triangular prism base base face face vertex A triangular prism has five faces. Its base is a triangle. (Notice that even when the triangular prism sits on a rectangle, the base is still a triangle.) Two of its faces are triangles; three of its faces are rectangles. It has six vertices and nine edges.

Rectangular pyramid face vertex base A rectangular pyramid has 5 faces. Its base is a rectangle or a square and the other 4 faces are triangles. It has 8 edges and 5 vertices.

vertex Triangular pyramid face base A triangular pyramid has four faces. All faces, including its base, are triangles. It has six edges and four vertices.

Presto! A triangular prism!

Presto! A triangular pyramid!

Presto! A square prism!

Presto! A square pyramid!

A prism is made of congruent shapes.

A pyramid is made of similar shapes that get smaller and smaller.

If you know the names of common polygons, then naming a prism or pyramid will be easy for you.

Look at the polygon on the bottom of the shape.

This polygon is a rectangle.

This shape is a rectangular prism.

This shape is a rectangular pyramid.

This is a pentagon.

This is a pentagonal prism.

This is a pentagonal pyramid.

This is an octagon.

This is an octagonal prism.

This is an octagonal pyramid.

If you know the common polygons and if you know the difference between a prism and a pyramid, naming these shapes is easy.

The only unique name that you have to remember is the “cube.”

A cube is a specific kind of rectangular prism.

A rectangular prism that has 6 congruent faces is called a cube.

A rectangular prism that has 6 congruent faces is called a cube.

A rectangular prism that has 6 congruent faces is called a cube.

A rectangular prism that has 6 congruent faces is called a cube.

A rectangular prism that has 6 congruent faces is called a cube.

A rectangular prism that has 6 congruent faces is called a cube.

The end.