Please help ill give brainiest

Find the value of the cosine for angle a

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn.if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.