This figure shows △ABC. AD¯¯¯¯¯ is the angle bisector of ∠BAC. What is BD?

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Help me please my teacher is kinda bad at teaching so I don't know what I'm doing

A triangle with vertices labeled as A, B, and C. Side A C is base. Side B C contains a midpoint D. A line segment is drawn from A to D, which bisects angle B A C into two parts labeled as B A D and D A C. Angles B A D and D A C are marked with one arc. Side A B is labeled 6. Base A C is labeled 8. Side D C is labeled 5.