Answer:
D = 55 feet
Explanation:
Let below sea level is negative direction and above sea level is positive direction.
A deep sea diver is at 45 feet below sea level = -45 feet
A helicopter is at 100 feet above sea level = +100 feet
We need to find the distance between the helicopter and deep sea diver. It can be calculated by simply adding the above data as follows:
D = -45 +100
= 55 feet
Hence, the distance between the helicopter and deep sea diver is 55 feet.