In △ABC, the bisector of ∠A intersects side BC at D. IF AB = 12 cm, AC = 15cm and BC = 18 cm, then the length of BD is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 8cm
Concept
Angle Bisector Theorem - An angle bisector divides the opposite side into two parts in the ratio of other two sides.
Application
AB / AC = BD / DC
12/15 = BD/DC
BD / DC = 4/5
BC = BD + DC
BC = 4 + 5 = 9 units
BC = 18 cm
9 units = 18 cm
1unit = 2 cm
BD = 2 x 4 = 8cm