The Angle Bisector Theorem: An internal angle bisector in a triangle divides the opposite side in the ratio of the other two sides. This diagram shows triangle ABC with angle bisector AD, where AB = 5, AC = 7, and BC = 6. The theorem states AB/AC = DB/DC, leading to the calculation of BD = 2.5.
Diagram illustrating the Angle Bisector Theorem, showing a triangle ABC with an angle bisector AD dividing side BC into segments BD and DC, with labeled lengths and the theorem formula AB/AC = DB/DC.