The word meaning 'equal in size' is 'equivalent;' it is used to describe identical measurements that may be expressed using different units or scales.
The word that means equal in size is 'equivalent.' When comparing measurements of different units, something that is equivalent has the same measurement but may be expressed in different units. For instance, 1 inch is equivalent to 2.54 centimeters, meaning both measurements represent the same length. Measurement is used in various contexts such as length, weight, and volume in both the metric and customary systems. In the metric system, prefixes like 'centi-' for 100 and 'kilo-' for 1,000 help us understand the scale of the measurement. The term equivalence is particularly important in mathematics to ensure that expressions on each side of an equality are dimensionally consistent, for example, when writing ratios or equations.