Fern's estimate is not correct because he rounded 548 wrong, it would be rounded to 550 instead since the number 8 is closer to 10. So the correct answer would be 420.
It would be D. because the volume of a sphere is 4/2 x pi x radius^3.
While it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton. In fact, the opposite occurred. Cotton growing became so profitable for the planters that it greatly increased their demand for both land and slave labor
B and c, anything with an x^2 term is a quadratic.
