Chapter 6.9, Problem 18HP

To determine

To explain: how you would solve the problem.

Explanation of Solution

Given information:

A real world example of when you might need to use indirect measurement.

Calculation:

Open ended:

Find the height of tallest electrical pole $AB=\text{}x\text{ft}$

Height of man is $CD=6\text{ft}$ .

Shadow length of man is $DE=10\text{ft}$ .

Length of the shadow of tower is $BE=20\text{ft}$

Observe the below figure:

  

Apply the similarity of triangles.

Consider the similar triangles $ABE$ and $CDE$ .

  $\begin{array}{c}\frac{AB}{BE}=\frac{CD}{DE}\\ \frac{x}{20}=\frac{6}{10}\\ 10x=20\times 6\\ x=\frac{20\times 6}{10}\\ x=12\end{array}$

Hence, the height of the house is $x=12$ ft.