Two vertical poles of equal height stand on opposite banks of a river. From a point on the river bank, 20m from the foot of the nearer pole, the angles of elevation of the tops of the nearer and the farther poles are 60∘ and 30∘ respectively. Find:
(a) the width of the river, and
(b) the height of each pole.
a. the width of the river
b. the height of each pole