[填空题]
Neptune is an average dista) o3v4;wirb5yyfw b /bnce of 4s9yi xsv 999jz.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. $\times 10^2$
