Identify the solid: which 3D form has two parallel, congruent polygonal bases connected by rectangular or parallelogram lateral faces, resulting in constant cross-section between the bases?
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APyramid
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BPrism
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CCone
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DTorus
Answer
Correct Answer: Prism
Explanation
Introduction / Context:Understanding standard solids is crucial for interpreting and creating drawings, calculating areas/volumes, and developing patterns. Prisms appear frequently in mechanical and architectural components due to their uniform cross-section and ease of fabrication.
Given Data / Assumptions:
- Two bases are equal (congruent) polygons.
- The bases are parallel to each other.
- Lateral faces join corresponding edges of the bases.
Concept / Approach:
A prism has two equal, parallel polygonal bases and lateral faces that are rectangles or parallelograms. This yields a constant cross-section along the axis normal to the bases. Contrast this with pyramids (one base and an apex) and cones (circular base with curved surface). A torus is a ring-shaped surface of revolution capturing none of these characteristics.
Step-by-Step Solution:
Check for the presence of two equal, parallel bases.Verify lateral faces connect matching base edges.Confirm cross-section is constant along the length.Conclude that the solid is a “Prism.”Verification / Alternative check:
Standard orthographic views of prisms show parallel top and bottom outlines; section views at multiple stations are identical. Development (pattern) unfolds into a series of equal rectangles corresponding to base edges.
Why Other Options Are Wrong:
Pyramid: single base plus apex; triangular sides.
Cone: circular base and curved surface.
Torus: circular ring surface with no polygonal bases.
Common Pitfalls:
Confusing a right prism (lateral faces rectangular) with an oblique prism (faces parallelogram); both are still prisms since bases remain parallel and congruent.
Final Answer:
Prism