Which prefix represents a factor of 1/100th of the base unit?

The prefix that represents a factor of 1/100th of the base unit is "centi-." In the metric system, "centi-" is derived from the Latin word "centum," which means one hundred. Therefore, when you see a unit prefixed with "centi-," such as centimeter (cm) or centiliter (cL), it indicates that the unit is being divided into one hundred equal parts.

For instance, one centimeter equals one hundredth of a meter, demonstrating how "centi-" modifies the base unit to reflect this fractional relationship. This understanding is fundamental in converting and comparing different metric units, making "centi-" a key prefix in measurements.