Let w be the river's width. Draw a scalene triangle with 100 ft as one side and internal angles of 105 and 60 degrees at each corner formed by that side. The two other sides will correspond to the sight lines. The opposite vertex will be the other side of the river. Use the Law of Sines to get the sides of the triangle. Once you have that, the river width can be obtained from a triangle side length and the sighting angle.
This is not about physics; it is pure trigonometry
in order to determine the width of a river, a base line of 100 ft is marked off on one side. On the other side of the river is a large rock. When sighted from each end of the base line it is found that the lines of sight make angles of 60 degrees and 75 degrees, respecively, with the base line.Determine the width of the river
1 answer
1 answer