You need to build a bridge across a river at a particular point. Moving parallel to the river for a distance, you note that the angle between the riverbank and the point on the opposite side is 60°. Moving a further distance of 150m the angle is now 30°.

What is the shortest distance the bridge can be?

Solution:

The length of the bridge is x

X = 150*sin60 = 129.90

So the shortest distance the bridge can be is 129.90 m