Multiple choice

In a triangle ABC, AD is the bisector of ∠BAC. If AB = 2.8 cm, AC = 4.9 cm and CD = 2.1 cm. then what is the length of BD? त्रिभुज ABC में ∠BAC का समद्विभाजक AD है। यदि AB = 2.8 सेमी. AC = 4.9 सेमी. और CD = 2.1 सेमी. तो BD की लम्बाई क्या है?

  1. 3.7 cm./सेमी.

  2. 0.8 cm./सेमी.

  3. 1.2 cm./सेमी.

  4. 1.0 cm./सेमी.
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C Correct answer
Explanation

By the Angle Bisector Theorem, in triangle ABC with angle bisector AD, we have: BD/DC = AB/AC. Given AB = 2.8 cm, AC = 4.9 cm, and DC = 2.1 cm. So BD/2.1 = 2.8/4.9, which gives BD/2.1 = 4/7, therefore BD = 2.1 x 4/7 = 1.2 cm.

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