[填空题]
Neptune is an average distav av3t.x uxc v7*08s;cshr9kjk 9nde/nce of 4dmn0evg6+ j .nic,,(g)ueo kt.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. $\times 10^2$
