A person standing on the bank of a river observes that the angle subtended by a tree on the opposite bank is 60∘, when he retires 40 feet from the bank he finds the angle to be 30∘. Find the height of the tree and the breadth of the river.
Open in App
Solution
Let h be the height of tree, then
h40=sin60o ∴h=20√3ft. hBQ=tan60o=√3,BQ=h√(3)=20ft. =breadth of the river.