In a triangle ABC, the bisector of angle BAC meets BC at a point D such that DC = 2BD. If AC-AB=5cm, then find the length of AB (in cm).
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 5
AD is the bisector of angle BAC
⇒ AB/AC = BD/DC
⇒ AB/(AB + 5) = BD/2BD
⇒ AB/(AB + 5) = 1/2
⇒ 2 × AB = AB + 5
AB = 5