As observed from the top of a 75 m tall lighthouse, the angles of depression of two ships are 30° and 45°. If one ship is exactly behind the other on the same side of the lighthouse, find the distance between the two ships.
Let the distance between the two ships be 
(m.)
And distance between the ship and foot of light house is 
(m.)
In ∆ABD
tan 45° = 
1 = 
AB = BD
75 = 
--------(1)
In ∆ABC
tan 30° = 
tan 30° = 
= 75√3 --------(2)
On substituting value of 
in eqn. (2)
Therefore distance between the two ships is 
29