Using the number line, find the distance between the two numbers mathematically. A submarine launched a missile from 1.1 kilometers below the ocean's surface to an altitude of 7.8 kilometers above the ocean's surface. What was the distance between the point below the ocean's surface and the point above the ocean's surface?
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-5 -4 -3 -2 -1 0 1 2 3 4 5
a. 6.9 km
b. 6.7 km
c. 8.9 km
