We need to find the circumference of the earth.
The formula for the circumference is:
Where
C is circumference
r is radius
We know the radius of earth is 6 378.1 kilometers.
Plugging in 6378.1 into "r" and finding C:
![\begin{gathered} C=2\pi r \\ C=2\pi(6378.1) \\ C=40074.78\operatorname{km} \end{gathered}]()
The circumference is 40,074.78 kilometers.
This, in scientific notation is,
![4.007478*^{}10^4\operatorname{km}]()