Question

In a Δ ABC, AD is the bisector of ∠ A, meeting side BC at D. If AB = 3.5 cm, AC = 4.2 cm, and DC = 2.8 cm, find BD.

Answer 1

Given: Δ ABC and AD bisects ∠A, meeting side BC at D. And AB = 3.5 cm, AC = 4.2 cm, and DC = 2.8 cm. 

Required to find: BD

Since, AD is the bisector of ∠A meeting side BC at D in Δ ABC 

⇒ \(\frac{AB}{AC}\) = \(\frac{BD}{DC}\) 

\(\frac{3.5}{4.2}\) = \(\frac{BD}{2.8}\) 

4.2 x BD = 3.5 x 2.8 

BD = \(\frac{7}{3}\) 

∴ BD = 2.3 cm