The longest length among one yard, one kilometer, one meter, and one inch is one kilometer.
What is the longest length?
The longest length among one yard, one kilometer, one meter, and one inch is one kilometer.
A kilometer is longer than a yard and a meter. One kilometer is equal to 1000 meters, while one yard is equal to 0.9144 meters.
Similarly, one meter is slightly longer than one yard. Therefore, one kilometer is the longest length among the options provided