Three-Dimensional Shapes
Three-Dimensional Shapes
Definition Solid Geometry
Solid geometry studies three-dimensional shapes, such as cubes, cylinders, and spheres. The diagrams show examples of these shapes.
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Definition Surface
A surface is the exterior of a three-dimensional shape.
Definition Face
A face is a flat surface of a three-dimensional shape.
Definition Edge
An edge is a line segment where two faces meet.
Definition Vertex
A vertex is a point where two or more edges meet.
Example
Drawing three-Dimensional Shapes
Method Drawing 3D Shapes
When drawing 3D shapes, some edges are hidden because they are at the back of the shape. We call these hidden edges. To show the shape clearly, we use dotted lines for hidden edges. This helps us see the shape and its depth.
Classification
Definition Classification
| Name | Shape | Faces | Edges | Vertices |
| Cube |  | 6 (flat) | 12 | 8 |
| Sphere | | 1 (curved) | 0 | 0 |
| Square Pyramid |  | 5 (flat) | 8 | 5 |
| Cylinder |  | 3 (2 curved, 1 flat) | 0 | 0 |