F(x) = -9 + 10.3x probably. It's definitely not the first or last option as they have negative gradients (i.e. negative x-coefficient) and so represent a negative correlation. The data given tells us there is a positive gradient and so a positive correlation. It could be the second option as the second and third are not so vastly different but I would go for the third because it appears to most closely fit the data pattern.
the diameter is 57.2 in, then the radius is half that, or 28.6 in. The volume of a sphere is V = (4/3)πr³, and so the volume of this hemisphere is (2/3)πr³