#### Answer

d=m/v
d=density (g/$cm^{3}$)
m=mass (g)
v=volume ($cm^{3}$)

#### Work Step by Step

This question is asking us to rank spheres of equal size by mass, from lightest to heaviest. We are given the densities of all three spheres, as well as the fact that all the spheres are equal sizes. This allows us to use the density formula to solve the problem. The formula is d=m/v, where d=density, m=mass, and v=volume. Since it is stated that all the spheres are of equal size, we can conclude that all have equal volumes. This means the only difference in density will result from mass. The sphere with the largest mass will have the largest density. We are told the spheres are aluminum (density= 2.7 (g/$cm^{3}$)), silver (density=10.49 (g/$cm^{3}$)), and nickel (density=8.9(g/$cm^{3}$)). Since aluminum has the smallest density, we can conclude that it also has the smallest mass. Silver, with the largest density, can be concluded to have the largest mass. Nickel lies in the middle. This means that ranking the masses from smallest to largest, it goes aluminum, nickel, silver.