extrapolation

Extrapolation is a way to estimate what something will be like in the future based on how it has been in the past. Think of it like a game you play when you were a kid. Let's say you were playing the game of tag. You know that if someone has run fast in the past, they might run fast again in the future. That is the same idea as extrapolation. We use the past to estimate what something might be like in the future.