Select the most suitable statement.
2023
Select the most suitable statement.
Answer: D. More than one of the above — ConceptA statement of the form “Every A is B” means that the set A is contained in the set B. A statement of the form “No A is B” means that the two sets have…
- A.
Every circle is an ellipse.
- B.
No circle is a hyperbola.
- C.
Every square is a rectangle.
- D.
More than one of the above
- E.
None of the above
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Correct answer: D
Concept
A statement of the form “Every A is B” means that the set A is contained in the set B. A statement of the form “No A is B” means that the two sets have no common member.
In inclusive geometric definitions, a more specialised figure can belong to a broader family when it satisfies all defining properties of that family.
Application
A circle is an ellipse whose two semi-axes are equal; equivalently, its eccentricity is 0. Therefore “Every circle is an ellipse” holds under the standard inclusive definition.
A circle is an ellipse with eccentricity 0, whereas a hyperbola has eccentricity greater than 1. Thus no non-degenerate circle is a hyperbola.
A square has four right angles and opposite sides parallel, so it satisfies every defining condition of a rectangle. Therefore every square is a rectangle.
Contrast and cross-check
“Every circle is an ellipse” is supported by the equal-semi-axis special case.
“No circle is a hyperbola” follows from the mutually different conic classes and eccentricities.
“Every square is a rectangle” follows from the inclusive hierarchy of quadrilaterals.
“None of the above” would require all three substantive statements to fail, which the definition checks rule out.
Result
Three substantive statements hold, so the suitable set-referential choice is “More than one of the above”.