does anyone have any idea how to solve this problem?

Question

The diameter of a certain atomic nucleus is 6.50x 10-5 pm and its mass is 9.40 x 10-25 g. What is the density of the nucleus in grams per centimeter cubed ? Assume the nucleus is a sphere with a volume equal to 4/3 P r 3

Answer 1

The radius is (1/2) (6.50 x 10^-5) = 3.25 x 10^-5 pm = 3.25 x 10^-15 cm (1 pm = 10^-12 m = 10^-10 cm).
V = 4/3 π r^3 = 4/3 π (3.25 x 10^-15)^3 = 1.438 x 10^-43 cm^3.
The density is ρ = m / V = 9.40 x 10^-25 / 1.438 x 10^-43
= 6.54 x 10^18 g / cm^3.

Answer 2

Part of the problem is that the nucleus of an atom is not a perfect sphere. The formula you have is useless.