Question

In the figure AD is the bisector of < BAC . AB = 4 cm and AC = 5 cm a) BD : DC = ____ : ____ b) What is the ratio of the areas of the triangles ABD and ADC ? c) If the area of the triangle ABD is 80 cm2 , what is the area of the triangle ADC ?

Answer 1

Answer:

your answer is 2.5cm

Step-by-step explanation:

Let the given ∆ABC be as drawn below:

Here, we can see that ∠BAC is bisected by AD where AD touches BC at D. BC=BD+DC where, BC=3cm . We also have the values of adjacent sides AB=6cm and AC=5cm .

These satisfy the requirements of angle bisector theorem. Then, by the theorem, we have:

ABBD=ACDC

⇒DC=AC∗BDAB=5∗36=2.5cm