Question

The angle of elevation of the top of a rock from the top and foot of a 100m gh tower are 30 and 45.find the height of Rock?

Answer 1

Let AB be the tower and DC be the rock.
Therefore, A/Q
AB=EC=100m
<DAE=30°
<EBC=45°
Let BC= AE= x m,
DE= h m
Now,
From ∆ECB
EC/BC= Tan 45°
100/x=1
x=100
Therefore,BC= 100m
Again
DE/AE=Tan 30°
h/100=1/√3
h=100/√3
Therefore DE=100/√3 m
The required height of the rock = DE + EC = (100+100/√3)m
=[100(1.732-1)/√3]m
=[100(0.732)/√3]m
=[73.2/√3]m
=42.26m

Answer 2

here,is the solution.