12. From the top of a 7 m high building, the angle of elevation of the top of a cable tower is 60° and the angle of depression of its foot is 45°. Determine the height of the tower.
Let the height of the cable tower be (AB = )m
Given,
Height of the building is 7 m and angle of elevation of the top of the tower , angle of depression of its foot .
According to question,
In triangle ,
since DB = CE = 7 m
In triangle ,
Thus, the total height of the tower equal to