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.
X is 10, L is 50 and V is 5. In Roman Numerals, when a letter is preceded by smaller letter ( in value), the latter's value is subtracted from the larger number's value, thus 10 (X) is subtracted from 50 (L), then add V which is 5. jb Â· 10 years ago.