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In the following figure, in \(\Delta ABC\) ray BD bisects \(\angle ABC\), A – D – C, seg ED \(\parallel\) side BC, A – E – B, then to prove that \(\dfrac{AB}{BC} = \dfrac{AE}{EB}\), complete the following activity.[Figure: \(\Delta ABC\) with A at th…

Q.3 (A)(i) In the following figure, in \(\Delta ABC\) ray BD bisects \(\angle ABC\), A – D – C, seg ED \(\parallel\) side BC, A – E – B, then to prove that \(\dfrac{AB}{BC} = \dfrac{AE}{EB}\), complete the following activity.

[Figure: \(\Delta ABC\) with A at the top, B at the lower left and C at the lower right; D is on side AC and ray BD is drawn and extended beyond D with an arrow; E is on side AB; seg ED is drawn parallel to BC; the two equal parts of \(\angle ABC\) are marked at B.]

Activity : In \(\Delta ABC\), ray BD bisects \(\angle B\).

\(\therefore \dfrac{AB}{BC} = \dfrac{\text{____}}{\text{____}}\) .............. (I) (Angle bisector theorem)

In \(\Delta ABC\), seg ED \(\parallel\) side BC.

\(\therefore \dfrac{AE}{EB} = \dfrac{\text{____}}{DC}\) .............. (II) ____

\(\therefore \dfrac{AB}{\text{____}} = \dfrac{\text{____}}{EB}\) .............. from (I) and (II)

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Best answer

Answer: (I) \(\dfrac{AB}{BC} = \dfrac{AD}{DC}\); (II) \(\dfrac{AE}{EB} = \dfrac{AD}{DC}\), Basic proportionality theorem; \(\therefore \dfrac{AB}{BC} = \dfrac{AE}{EB}\).

Activity completed:

In \(\Delta ABC\), ray BD bisects \(\angle B\).

\(\therefore \dfrac{AB}{BC} = \dfrac{AD}{DC}\) .............. (I) (Angle bisector theorem)

In \(\Delta ABC\), seg ED \(\parallel\) side BC.

\(\therefore \dfrac{AE}{EB} = \dfrac{AD}{DC}\) .............. (II) (Basic proportionality theorem)

\(\therefore \dfrac{AB}{BC} = \dfrac{AE}{EB}\) .............. from (I) and (II)

In (II), ED \(\parallel\) BC in \(\Delta ABC\) gives \(\dfrac{AE}{EB} = \dfrac{AD}{DC}\); comparing its right-hand side with (I) gives the required result.

Doubtly AI · 25 Oct 2026 AI-verified · Oct 2026 Report
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