The top of a hill rises 171 feet above checkpoint 4.
From the given table, checkpoint 4 is at -183 feet above sea level.
This means that the top of the hill is
[tex]171+(-183)=171-183=-12\: \text{feet}[/tex]
Therefore, the altitude of the top of the hill is -12 feet.
Part (b)
How much lower is checkpoint 5 than checkpoint 1?
From the given table, checkpoint 1 is at 1,415 feet and checkpoint 5 is at -132 feet above sea level
The difference between them is
[tex]1,415-(-132)=1,415+132=1547\text{ feet}[/tex]
Therefore, checkpoint 5 is 1547 feet lower than checkpoint 1.
