16. Find the distance between the ships

A helicopter locates two ships $A$ and $B$ from the top of an ocean. The pilot finds that the helicopter is exactly at the top of the ship $A$. If the distance of the helicopter from ship $A$ is 39 $km$ and that of ship $B$ is 89 $km$, how far are the ships from each other?

 

 

Answer:

 

The ship $A$ is  $km$ far from ship $B$.