Q) In the given figure, DE ∥ AC and DF ∥ AE. Prove that : BF/FE = BE/EC.

(Q 22 – 30/4/2 – CBSE 2026 Question Paper)
Ans:
Step 1: Let’s compare Δ ABE and Δ DBF 
Here, ∠ BDF = ∠ BAE
(∵ DF ǁ AE)
∠ B = ∠ B (common angle)
By AA Similarity criterion, Δ ABE ~ Δ DBF
∴ ![]()
∴ ![]()
∴ ![]()
∴
………….. (i)
Step 2: Let’s compare Δ ABC and Δ DBE 
Here, ∠ BDE = ∠ BAC
(∵ DE ǁ AC)
∠ B = ∠ B (common angle)
By AA Similarity criterion,
Δ ABC ~ Δ DBE
∴ ![]()
∴ ![]()
∴ ![]()
∴
………. (ii)
Step 3: By comparing equations (i) and (ii), we get:
∴ ![]()
by inversing both sides, we get:
∴
Hence proved !
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