InterviewSolution
Saved Bookmarks
| 1. |
In ΔABC, the bisector of ∠A intersects side BC at D. If AB = 12 cm, AC = 15 cm and BC = 18 cm, then the length of BD is1. 8 cm2. 9.6 cm3. 7.5 cm4. 9 cm |
|
Answer» Correct Answer - Option 1 : 8 cm Given: AB = 12 cm AC = 15 cm BC = 18 cm Concept used: The angle bisector of an angle of a triangle divides the opposite side into two parts that are proportional to the other two sides of the triangle. Calculations: The length of BC is, BC = BD + DC ⇒ DC = 18 – BD Using the concept, ⇒ BD/DC = AB/AC ⇒ BD/(18 – BD) = 12/15 ⇒ BD/(18 – BD) = 4/5 ⇒ 5BD = 72 – 4BD ⇒ 9BD = 72 ⇒ BD = 8 cm ∴ The length of BD is 8 cm |
|