The angle of depression from the top of a light-house of two boats are 60° and 30° towards the west, if the two boats are 60m apart, then the height of the light house is
D = h (cotA - cotB) Here (h = height of light house) D = AB = 60 60 = h (cot30° - cot60°) 60 = h (√3-1/√3) 60 = h ((3-1)/√3) 2h/√3 = 60 m h = 60 × √3/2 = 30√3 m So height of the tower is = 30√3 m