[填空题]
Neptune is an average di c):4il 70qhe8bui2q ;moqrnp stan+;c6eey pb; taa(gfp-ce of 4.5 $\times 10^{9} \mathrm{~km}$ from the Sun. Estimate the length of the Neptunian
year given that the Earth is 1.50 $\times 10^{8} \mathrm{~km}$ from the Sun on the average. $\times 10^2$
