Inflate your height if the person you asked inflated it first. If they ask first then the conversation should go like this
"Hey how tall are you?" - the other person
"I don't know really, how tall are you?" - you
They then state their height and you say "Then I'm probably >insert your height with how many inches they inflated it by<"
If it's zero inflation then say your exact height, if it's 1 inches then say your height +1 inch etc