Geo quiz!! don’t understand at all

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.

Find the amplitude of a sinusoidal function that models this temperature variation

The triangles are similar. what is the value of x? enter your answer in the box.