A three-dimensional object is composed of flat faces that have identifiable two-dimensional shapes; for example, a cube has square faces, a rectangular prism has rectangular faces, and a triangular prism has triangular and rectangular faces. The learner matches a face’s shape regardless of its orientation and distinguishes flat faces from curved surfaces, without yet analyzing nets, surface area, or more advanced geometric properties.
A face is a flat surface on a 3D object. Each face has a 2D shape, such as a triangle, square, or rectangle.
To match a 3D object to its 2D faces:
Example: A triangular prism has faces like this:
So, the 2D shapes that match a triangular prism are triangles and rectangles.
The triangular faces might point up, down, or sideways, but they are still triangles. The rectangular faces might also be turned, but they are still rectangles.
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