Q1. [1] § 6.3 Similarity of Triangles § 6.4 Criteria for Similarity of Triangles § 6.5 Summary
In triangles ABC and PQR, $\angle A = \angle Q$ and $\angle B = \angle R$, then AB : AC is equal to :
- A PQ : PR
- B PQ : QR
- C QR : QP
- D PR : QR
Previously asked in CBSE board exam
2026 30/2/1 Q8
Generated by claude-sonnet-4-6 · 2026-06-15 10:25 · grounding rag
Model Answer
Option (C): QR : QP
Since ∠A = ∠Q and ∠B = ∠R, by AA similarity criterion, △ABC ~ △QRP.
Therefore, AB/QR = AC/QP, so AB : AC = QR : QP.
Explanation
- Match corresponding vertices carefully: A↔Q, B↔R, C↔P, giving △ABC ~ △QRP.
- Corresponding sides are AB/QR = BC/RP = AC/QP.
- So AB : AC = QR : QP — option C.
- The common mistake is writing △ABC ~ △PQR without checking which angles correspond, leading to wrong ratios.
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