More Questions from Data Sufficiency

Are triangles ΔABC and ΔPQR congruent? I. Areas of ΔABC and ΔPQR are equal. II. ΔABC and ΔPQR are right triangles.

Verbal Reasoning Data Sufficiency Difficulty: Medium
Choose an option
  • A
    Statement I alone is sufficient to answer the question.
  • B
    Statement II alone is sufficient to answer the question.
  • C
    Statements I and II together are necessary to answer the question.
  • D
    Statements I and II together are not sufficient to answer the question.

Answer

Correct Answer: Statements I and II together are not sufficient to answer the question.

Explanation

Introduction / Context:Triangle congruence typically requires side-angle-side (SAS), side-side-side (SSS), angle-side-angle (ASA), or right-angle-hypotenuse-side (RHS) information. Equal area and both being right-angled do not automatically imply congruence.

Given Data / Assumptions:

  • Statement I: area(ΔABC) = area(ΔPQR).
  • Statement II: both triangles are right triangles.

Concept / Approach:Equal area does not fix shape or side lengths; many non-congruent triangles can share the same area. Knowing both are right triangles still leaves infinitely many non-congruent possibilities with the same area (different legs producing the same 1/2 * leg1 * leg2).

Step-by-Step Solution:With I alone: triangles can have equal areas yet different side sets ⇒ not sufficient.With II alone: both right-angled does not determine equality of corresponding sides ⇒ not sufficient.With I and II together: right triangles with area A can be formed by infinitely many integer or real leg pairs (x, 2A/x), leading to different hypotenuse lengths. Hence still not sufficient to conclude congruence.

Verification / Alternative check:Example: Right triangles with legs (3,8) and (4,6) both have area 12 but are not congruent.

Why Other Options Are Wrong:Neither statement alone reaches a congruence criterion; together they also fall short of SAS/SSS/ASA/RHS with matching corresponding measures.

Common Pitfalls:Confusing equal area with congruence; congruence requires stricter conditions.

Final Answer:Statements I and II together are not sufficient to assert congruence.

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