In total, how many words are there using these particular combinations of letters?You could make 15 words from the combination you searched for.
What's the highest scoring word you can play in Scrabble ?One could make 'riffi' scoring 11 points in Scrabble.
How many characters are in the largest word from this list?The longest word that's possible to construct from words that start with 'ri' and end with 'i' is 'rifacimenti', and it is made up of 11 letters.