An aeroplane at an altitude of $1500 \mathrm{m}$ finds that two ships are sailing towards it in the same direction. The angles of depression as observed from the aeroplane are $45°$ and $30°$, respectively. Find the distance between the two ships in metres.

In the adjoining figure, from the top of a building $AB=60 \mathrm{m}$ high, the angles of depression of the top and bottom of a vertical lamp-post $CD$ are observed to be $30°$ and $60°$, respectively. Find the horizontal distance observed (in metres) between $AB$ and $CD$.

In the adjoining figure, from the top of a building $AB$$=60 \mathrm{m}$ high, the angles of depression of the top and bottom of a vertical lamp-post $CD$ are observed to be $30°$ and $60°$, respectively. Find the height of the lamp-post in metres.

Find the horizontal distance between $BA$ and $CD$