Same chapter3 marksDifficulty: Medium
In triangle ABC, AB = AC and D is the midpoint of BC. Prove that AD is perpendicular to BC.
Triangles
3 marksDifficulty: Medium
Explain why SSA is not a valid criterion for the congruency of two triangles.
Original Khojo Papers practice question — not from a past board paper.
Answer
Given two sides and an angle not between them, two different triangles can often be drawn: the third side can meet the second arm of the angle at either of two points, giving an acute-angled and an obtuse-angled possibility. The data therefore do not determine the triangle uniquely.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The only case where it does work is when the given angle is a right angle, which is the RHS rule.
Related questions
From the same topic and chapter, at a similar level.
Same chapter3 marksDifficulty: Medium
In triangles ABC and PQR, AB = PQ, BC = QR and angle B = angle Q. State the criterion by which the triangles are congruent and name three pairs of equal parts that follow.
Triangles
Same chapter3 marksDifficulty: Medium
Prove that the angles opposite to the equal sides of an isosceles triangle are equal.
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Same chapter3 marksDifficulty: Medium
In an isosceles triangle ABC, AB = AC and ∠A = 40°. Find ∠B and ∠C.
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Same chapter2 marksDifficulty: Easy
State the four conditions of congruency of two triangles.
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Same chapter1 markDifficulty: Easy
Two triangles are congruent by the RHS rule when:
Triangles