The angle of elevation of the top of an unfinished tower at a point distance 80m from its base is 30 degree.How much higher must the tower be raised so that its angle of elevation at the same point may be 60 degree?

Asked by araima2001 | 8th Nov, 2015, 11:55: AM

Expert Answer:

 
 
 
 
 
 
 
 
 
 
 
L e t space A B space b e space t h e space t o w e r space a n d space straight P space b e space t h e space p o i n t space o f space o b s e r v a t i o n space m a k i n g space a n g l e space o f space e l e v a t i o n space 30 degree. L e t space B C space b e space t h e space r a i s e d space h e i g h t space s o space t h a t space t h e space space a n g l e space o f space e l e v a t i o n space a t space p o i n t space straight P space i s space 60 degree  I n space increment space A P B t a n space 30 degree equals fraction numerator A B over denominator A P end fraction fraction numerator 1 over denominator square root of 3 end fraction equals fraction numerator A B over denominator 80 end fraction A B equals fraction numerator 80 over denominator square root of 3 end fraction straight m  I n space increment space A P C t a n space 60 degree equals fraction numerator A C over denominator A P end fraction square root of 3 equals fraction numerator A B plus B C over denominator 80 end fraction fraction numerator 80 over denominator square root of 3 end fraction plus B C equals 80 square root of 3 B C equals fraction numerator 160 over denominator square root of 3 end fraction straight m  S o space h e i g h t space o f space t h e space t o w e r space m u s t space b e space r a i s e d space b y space fraction numerator 160 over denominator square root of 3 end fraction straight m space s o space t h a t space t h e space space a n g l e space o f space e l e v a t i o n space a t space p o i n t space straight P space i s space 60 degree
 
 
 
 
 
 
 
 

Answered by Vijaykumar Wani | 9th Nov, 2015, 04:45: PM

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