A rotating wheel has been used to measure distance since ancient times.
circumference of a wheel in meters =
= PI() * (diameter of the wheel in meters)
distance in meters =
= (circumference of the wheel in meters) * (number of rotations)
number of rotations =
= (distance in meters) / (circumference of the wheel)
If the wheel is rotating at a constant speed:
number of rotations =
= (number of rotations per unit of time) * (unit of time)
