[20 points]
earth's outer core can be modeled by a spherical shell that extends from a distance of approximately 1,200 kilometers from earth's center to approximately 3,400 kilometers from earth's center. which of the following is closest to the volume of earth's outer core, in cubic kilometers?
a) 1.52 x 10^7
b) 3.18 x 10^7
c) 4.46 x 10^10
d) 1.57 x 10^11
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