Same chapter3 marksDifficulty: Medium
Explain why SSA is not a valid criterion for the congruency of two triangles.
Triangles
3 marksDifficulty: Medium
In triangle ABC, AB = AC and D is the midpoint of BC. Prove that AD is perpendicular to BC.
Original Khojo Papers practice question — not from a past board paper.
Answer
Triangles ABD and ACD have AB = AC, BD = DC and AD common, so they are congruent by SSS. Hence angle ADB = angle ADC, and since together they make a straight angle each is 90°.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The same argument shows that AD bisects the vertex angle A.
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