The angle of elevation of the rope of a tree from a point A on the ground is 60∘ . On walking 20m away from its base to a point B, the angle of elevation changes to 30∘. Find the height of the tree.
10√3
In triangle ACD
tanɵ = DCCA = hx
tan60∘ = √3 = hx ..................... 1
in triangle CDB
tan30∘ = CDCB
1√3 = hx + 20.......................2
Solving 1 and 2, we get h= 10√3