Consider a triangle ABC with AB = 4, BC = 5 and CA = 3. Let D be the point of intersection of the bisector of the angle A and the edge BC. Find the length of AD. Obs: I already know how to solve this question(since its written in the answer sweet), but I wanted to solve using another method. I used the talles theorem to find BD and DC, so i tried to use cosines law to isolate cosine and substitute on the another equation, but I keep getting the wrong answer. I want to know another ways to solve it, and know the reason why i'm getting the wrong answer. BTW, the answer is 12sqrt(2)/7.
