Session 2: Three-Dimensional Shapes – Definition, Types and Interactives

What are Three-Dimensional Shapes?

A solid shape has a dimension of three. It has length, width and height.

Length, width and height are the dimensions of a three-dimensional figure. Examples of three-dimensional shapes are:

Let us learn more about three-dimensional shapes and their properties.

Three-Dimensional Shape: Prism

A prism is a solid with two equal polygon bases that are parallel and connected by rectangles. Prisms are named by their base shape. A cuboid is also a prism.

 

Three-Dimensional Shape: Cuboid

Faces:

A cuboid is made up of six rectangular faces. 

They are  (the top face),  (the bottom face),  (the right side),  (the left side),  (the back face) and  (the front face). As part of a three-dimensional figure, they are two-dimensional shapes. 

Edges: 

Any two adjacent faces of a cuboid meet in a line segment, which is called an edge of the cuboid.

Although the figure is three-dimensional, each edge is only a line segment, and so is one-dimensional. There are 12 edges of the cuboid. They are  and .

Vertices:

Any two edges of a cuboid meet a point, which is called a vertex of the cuboid. 

A cuboid has 8 vertices. They are  and H.  

Although the cuboid is three-dimensional, each vertex is simply a location in space, and as such has zero dimensions. 

Three-Dimensional Shape: Pyramid

A pyramid is a three-dimensional solid with a polygonal base. Each corner of a polygon is attached to a singular vertex, which gives the pyramid its distinctive shape. Each base edge and the vertex form a triangle. Pyramids are named by their base shape.

Three-Dimensional Shape: Cylinder

A cylinder is a three-dimensional solid consisting of two equal, parallel, circular sides (the bases), joined by a curved surface.

Three-Dimensional Shape: Cone

A cone is a three-dimensional solid with a circular base whose lateral surface meets at a point called the vertex.

Three-Dimensional Shape: Sphere

A sphere is the set of all points in space at an equal distance from a center point. The distance from the center point to the sphere is called the radius.

 Remember this!

• A solid shape has three dimensions. It occupies space and has length, width and height. 
• The sides that make up a solid shape are called their faces. 
• The line segment where two faces meet is called an edge. 
• A vertex or a corner is a point where two or more edges meet. 
• Cuboids, pyramids, cones, cylinders and spheres are some three-dimensional shapes. These are defined by their base shapes, a number of vertices and other properties.