In a triangle ABC, AD is the angle bisector of angle A. If AB = 8.4 cm and AC = 5.6 cm and DC = 2.8 cm, then the length of side BC will be :

4.2 cm 5.6 cm  7 cm  2.8 cm

7 cm

⇒ According to the concept, ⇒ \(\frac{AB}{AC}\) = \(\frac{BD}{DC}\) ⇒ \(\frac{8.4}{5.6}\) = \(\frac{BD}{2.8}\) ⇒ \(\frac{8.4}{2}\) = BD ⇒ 4.2 = BD So, BD + DC = BC ⇒ BC = 4.2 + 2.8 = 7 cm Therefore, the length of BC is 7 cm.