Question

A man standing on a bank of a river found that the angle of elevation of a tree on the other bank of the river is 60° . By retiring 40m back he found the angle of elevation to be 30° . Find the hight of the tree and breadth of the river.

Answer 1

Answer:

let height of the tree be h and breadth of the river be b

tan 60 = h/b

√3 = h/b

h = b√3

tan 30 = h/(b+40)

1/√3 = h/(b+40)

1/√3=b√3/(b+40)

b√3.√3=b+40

3b-b=40

b=20

h=20.√3