Question

A surveyor measures the distance across a straight river by the following method: Starting directly across from a tree on the opposite bank, he walks x = 108 m along the riverbank to establish a baseline. Then he sights across to the tree. The angle from his baseline to the tree is θ = 30.8°. How wide is the river?

Answer 1

Using simple trigonometry,

tanθ = perpendicular/base

Tan(30.8) = x/108

Width, x = 64.38 m

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