Laravel

Chapters For Class X- CBSE


Heights and Distances


Example:The angle of elevation of the top of tower observed by two observer P and Q standing in a straight line with the tower ,at a distance of a meter from each other is 45° and 60° . Find the height of the tower?


45° 60° A B P Q a meters x meter 
Given ,distance between two observer P and Q be a meters.
Let the height of tower be h meter
Let the distance between observer Q and base of tower be x meter

In ∆QAB , tan 65° = hx 
           3 = hx
		   x = h3 => 3h3  ......(1)
		   
In ∆PAB ,  tan 45° = ha+x
               1 = ha+x
			   h = a+x
substitute the value of x from eqn (1) in above eqn.
 Therefore    h = a+3h3
          =>  h−3h3  = a
		  =>  3h−3h3  = a
		  => h = 3a3−3 => (3+3)a2