Chapter 8.5, Problem 11PPS

To determine

The width of the river.

Answer to Problem 11PPS

  $1309\text{ft}$

Explanation of Solution

Given:

  

Calculation:

The figure can be drawn as:

  

According to the definition of tangent,

  $\begin{array}{l}\tan 45°=\frac{630}{AH}\\ AH=\frac{630}{\tan 45°}\\ AH=630\\ \text{and}\\ \tan 18°=\frac{630}{GH}\\ GH=\frac{630}{\tan 18°}\\ GA+AH=\frac{630}{\tan 18°}\\ x+630=\frac{630}{\tan 18°}\\ x+630\approx 1939\\ x\approx 1309\text{ft}\end{array}$