- A≅
- B~
- C=
- D∝
Step-by-Step Solution
The symbol ≅ denotes congruence. The symbol ~ denotes similarity, = denotes equality of numbers, and ∝ denotes proportionality.
Answer: A) ≅
Which of the following is the correct symbol used to denote that two triangles are congruent?
Class 9Triangles (Congruence)Geometry — Triangles
Key idea: The four valid congruence criteria
**SSS**: All three sides equal → congruent.
**SAS**: Two sides + included angle equal → congruent.
IMPORTANT: the angle must be BETWEEN the two given sides. SSA (two sides + non-included angle) is NOT a valid criterion in general.
**ASA**: Two angles + included side equal → congruent.
**AAS**: Two angles + a non-included side equal → congruent (since the third angle is forced by 180°).
**RHS** (right triangles only): Right angle + hypotenuse + one side equal → congruent.
**Once congruent, all corresponding parts are equal (CPCT)** — that's the lemma you cite to extract any matching side or angle in the next step of a proof.
**SAS**: Two sides + included angle equal → congruent.
IMPORTANT: the angle must be BETWEEN the two given sides. SSA (two sides + non-included angle) is NOT a valid criterion in general.
**ASA**: Two angles + included side equal → congruent.
**AAS**: Two angles + a non-included side equal → congruent (since the third angle is forced by 180°).
**RHS** (right triangles only): Right angle + hypotenuse + one side equal → congruent.
**Once congruent, all corresponding parts are equal (CPCT)** — that's the lemma you cite to extract any matching side or angle in the next step of a proof.
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Practice 5 Similar Questions Free →All Triangles (Congruence) practice questions
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In ΔABC and ΔDEF, AB = DE = 6 cm, ∠A = ∠D = 70°, AC = DF = 4 cm. Are the triangles…In ΔABC, the exterior angle at C is 110° and ∠A = 65°. Find ∠B (in degrees).If the perpendicular from the vertex A of an isosceles triangle (AB = AC) meets BC at D,…Which congruence criterion applies specifically to two right-angled triangles when their…In ΔABC, D is the midpoint of BC and AD ⊥ BC. Which statement is correct?