22. Five mark example problem IX

A man is watching a boat speeding away from the top of a tower. The boat makes an angle of depression of \(60^{\circ}\) with the man's eye when at a distance of \(200 \ m\) from the tower. After \(10\) seconds, the angle of depression becomes \(45^{\circ}\). What is the approximate speed of the boat (in \(km / hr\)), assuming that it is sailing in still water? (\(\sqrt{3} = 1.732\))

 

Answer:

 

The speed of the boat \(=\)  \(km / hr\).