1. Twenty centimeters are equivalent to two hundredths of a meter.2. The terms "centimeter" and "cm" are used interchangeably, with 1 centimeter precisely equal to 10 millimeters.3. Consequently, twenty centimeters are officially defined as twenty millimeters.4. This conversion is based on the International System of Units (SI), which aims to provide a universal standard for measurement.5. Such standards facilitate easy conversion and comparison of length measurements across different contexts.