Koichi passed ten runners on the final lap.
Koichi can run one lap of the track in three to four minutes.
The Tofugu team is going to make a trip around the world, so the office will be closed for about a year.
One circumference is one time around. How many times will you go around the moon? Just 一周?
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Note that the いち becomes いっ as it often does when being used in a counter (一階, 一回, etc.).