Question

In a ΔABC, AD is the bisector of ∠A, meeting side BC at D.

If AC = 4.2 cm, DC = 6 cm and 10 cm, find AB

Answer 1

We have,

BC = 10 cm, DC = 6 cm and AC = 4.2 cm

∴ BD = BC – DC = 10 – 6 = 4 cm

⇒ BD = 4 cm

In ΔABC, AD is the bisector of ∠A.

We know that, the internal bisector of an angle of a triangle divides the opposite side internally in the ratio of the sides containing the angle.

`therefore"BD"/"DC"="AB"/"AC"`

`rArr4/6="AB"/4.2`        [∵ BD = 4 cm]

⇒ AB = 2.8 cm