Technical Drawing — A polyhedron is regular only if its faces are congruent regular polygons and the same number of faces meet at every vertex; equal regular faces alone do not guarantee regularity.

Difficulty: Medium

Correct Answer: Incorrect

Explanation:


Introduction / Context:
Regular polyhedra (Platonic solids) are highly symmetric: every face is a congruent regular polygon and the vertex configuration is identical everywhere. Saying “equal regular faces” by itself is not sufficient to declare a polyhedron regular.


Given Data / Assumptions:

  • Faces may be congruent regular polygons.
  • Vertex configuration may or may not be uniform.
  • Regularity requires both conditions: equal regular faces and identical vertex arrangement.


Concept / Approach:
The definition of a regular polyhedron has two parts: face regularity and vertex uniformity. Many solids violate vertex uniformity even if their faces are all regular and congruent, making them non-regular.


Step-by-Step Solution:
1) Check that each face is a congruent regular polygon.2) Examine each vertex: the count and order of faces must be identical at every vertex.3) Confirm global symmetry consistent with Platonic solids.4) If vertex configuration differs, the solid is not regular.


Verification / Alternative check:
Compare with known Platonic solids (tetrahedron, cube, octahedron, dodecahedron, icosahedron). Any deviation in vertex configuration disqualifies regularity.


Why Other Options Are Wrong:
“Correct” overlooks the vertex condition; “True for any prism with square faces” is false—prisms do not have identical vertex configurations matching Platonic criteria; “Regardless of vertices” ignores the definition; “Surface area equality” is irrelevant to regularity.


Common Pitfalls:
Assuming face congruence implies overall regularity; neglecting vertex conditions; confusing uniform/semiregular classes with regular ones.


Final Answer:
Incorrect

More Questions from Technical Sketching

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion