Explanation:
this is just plain multiplication.
we know how far it travels on one day.
that multiplied by 365.25 is his fast it travels in one year.
that multiplied by 800 gives us how fast it travels in 800 years.
5.782 × 10⁸ × 365.25 × 800 = 5.782×365.25×800 × 10⁸ =
= 1,689,500.4 × 10⁸ = 1.6895004 × 10¹⁴ km