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.
Roman Numerals Chart 1-100. Here is a chart of what each Roman Numeral stands for. The system is based on seven different symbols. These symbols can be used to write any number from 1 to 3,999!Below are the numbers for 1-100.ere is a chart of what each Roman Numeral stands for. The system is based on seven different symbols. These symbols can be used to write any number from 1 to 3,999! Below are the numbers for 1-100.