Actually, it is not polite to ask people what pant sizes they are wearing. Its none of your business anyway. I don't go asking people in real life what pant size they are wearing because they will feel offend by it and it is RUDE. Not polite to be asking that kind of question. 
How would you like if I ask what is your penis size? Bra size? I mean that is absurd, no need to know.
