If one traveled along the circumference of the equator, he will go ##40030## ##km## – to the nearest kilometer.
Assuming questioner is referring to earth and its known radius is ##6371## ##km## and that it is a perfect circle at equator with this radius,
As circumference of a circle is given by ##2pir##
If one traveled along the circumference of the equator,
he will go ##2pixx6371=2xx3.14159xx6371=40030.14## ##km## or to the nearest kilometer, it would be ##40030## ##km##.