Chapter MPS, Problem 14.9MPS

To determine

Find the length of the pond.

Answer to Problem 14.9MPS

  $19.55$

Explanation of Solution

Given information:

Determine the length $l$ of the pond.

  

Calculation:

Consider the figure:

  

Use cosine rule,

  $\begin{array}{l}{l}^2=a^2+b^2-2ab\cos \theta \\ ={30}^2+{20}^2-2(30)(20)\cos (0.7rad)\\ =900+400-1200(0.764842)\\ =1300-917.8104\\ =382.1896\\ l=\sqrt{382.1896}\\ \approx 19.55\end{array}$

Hence, the length $l$ is $19.55$ .