A pyramid is a polyhedron whose lateral faces are

Options

A. Rectangles
B. Triangles
C. Parallelograms
D. Rhombuses or Rhombi

Answer

To answer the question "A pyramid is a polyhedron whose lateral faces are...", we need to understand the properties of a pyramid and its lateral faces.

### Step-by-Step Solution:

1. **Definition of a Pyramid**: A pyramid is a three-dimensional geometric figure that has a polygonal base and triangular lateral faces that meet at a common point called the apex.

**Hint**: Remember that a pyramid has one base and triangular faces.

2. **Identifying Lateral Faces**: The lateral faces of a pyramid are the triangular faces that connect the base to the apex. Each side of the base corresponds to one triangular lateral face.

**Hint**: Visualize the pyramid and count the triangular faces that rise from the base to the apex.

3. **Congruency of Lateral Faces**: In a pyramid, the lateral faces can be congruent or not, depending on the shape of the base. For example, in a regular pyramid (where the base is a regular polygon), all lateral faces are congruent triangles. However, in an irregular pyramid, the lateral faces may not be congruent.

**Hint**: Think about different types of pyramids, like a square pyramid versus a triangular pyramid.

4. **Conclusion**: Therefore, we can conclude that a pyramid is a polyhedron whose lateral faces are triangular.

**Hint**: Remember that the defining characteristic of the lateral faces of a pyramid is that they are always triangles.

### Final Answer:
A pyramid is a polyhedron whose lateral faces are triangular.