Q .From a point on a bridge across the river the angle of depression of the banks on opposite sides of the river are 45° and 45° respectively.
if the bridge is at the height of 3 from the banks. Find the width of the river (take √3 = 1.732 )

Height of bridge from the banks CD = 3m
∠CAD = 45°
∠CBD = 45°
so we have to calculate width of the river AB =?

So in △ACD according to basic concept-


AB : BC : CA = 1 : 1 : √2

CD = 1 part = 3m = AC

AC = 3

So in △BCD according to basic concept-



AB : BC : CA = 1 : 1 : √2

CD = 1 part = 3m = BC

BC = 3m

So width of the river AB = AC + BC
AB = 3 + 3
AB = 6m