PCO stands for Potential Change Order (construction management). Suggest new definition. This definition appears somewhat frequently and is found in the following Acronym Finder categories: 1  Business, finance, etc.
Quick Answer. The Roman numeral XIX is the number 19. X is the number 10, and I is the number one. When a lower number is placed in front of a larger number, it indicates subtraction; IX is the same as 10 minus one, which equals nine. The Ancient Romans used different letters to represent numbers.
MIX is a number used in the number system of ancient Rome, called Roman Numerals.We here at Research Maniacs think it's remarkable that Roman Numerals have stood the test of time and are still being used today.IX is a number used in the number system of ancient Rome, called Roman Numerals.We here at Research Maniacs think it's remarkable that Roman Numerals have stood the test of time and are still being used today.