Chapter 1.6, Problem 37E

To determine

To find:the change in elevationfrom $-120\text{ feet to }-90\text{ feet}$

Answer to Problem 37E

The change in elevation from $-120\text{ feet to }-90\text{ feet}$ is $30\text{ feet}$

Explanation of Solution

Given information:

Initial elevation, ${\text{H}}_{\text{i}}=-120\text{ feet}$

Final elevation, ${\text{H}}_{\text{f}}=-90\text{ feet}$

Calculation:

Subtract initial elevation from final elevation $\left({\text{H}}_{\text{f}}-{\text{H}}_{\text{i}}\right)$ to find the change in elevation,

  $\begin{array}{l}{\text{ H}}_{\text{f}}-{\text{H}}_{\text{i}}\\ =-90-\left(-120\right)\left[{\text{Substitute values of H}}_{\text{f}}{\text{ and H}}_{\text{i}}\right]\\ =-90+120\text{ [To subtract }\left(-120\right)\text{, add its opposite, 120}]\\ =30\left[\text{Add}\right]\end{array}$

Hence,the change in elevation from $-120\text{ feet to }-90\text{ feet}$ is $30\text{ feet}$