Question

In a ΔABC it is given that AD is the internal bisector of ∠A. If BD = 4 cm, DC = 5 cm and AB = 6 cm, then AC = ?

पर्याय

• 4.5 cm

• 8 cm

• 9 cm

• 7.5 cm

Answer 1

7.5 cm

Explanation:

Use the angle-bisector theorem: `(BD)/(DC) = (AB)/(AC)`.

So, `4/5 = 6/(AC)`

⇒ `AC = 6 xx 5/4` 

= `30/4`

= 7.5 cm