There are 10 words that start with 'extrap'.
| extrapolate | extrapolated | 
| extrapolates | extrapolator | 
| extrapolating | extrapolation | 
| extrapolative | extrapolators | 
| extrapolations | extrapyramidal | 
Note: These 10 words that start with 'extrap' are found from the USA & Canada version of the tournament Scrabble word list.