In ΔABC, D is a point on BC such that AD is the bisector of ∠A, AB = 11.7 cm, AC = 7.8 cm and BC = 13 cm. What is the length (in cm) of DC?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e 5.2
B the angle bisector theorem.
⇒ DC/AC = BD/AB
⇒ DC/7.8 = 13 - DC/11.7
⇒ 0.3DC = 2.6 - 0.2DC
⇒ DC = 2.6 / 0.5
⇒ DC = 5.2