question_answer

A person standing on the bank of a river. Observes that the angle subtended by a tree on the opposite bank is \[60{}^\circ \]. When he retires 20 m from the bank, he finds the angle to be \[30{}^\circ \]. Find the height of the tree.

A)  \[10\]                           

B)  \[20\,\sqrt{3}\]

C)  \[10\,\sqrt{3}\]

D)  \[30\,\sqrt{3}\]

E)  None of these