What is the length of the hypotenuse?

Fiona and her friends are playing a game by guessing where a coin will land when it is randomly dropped inside the square shown below. fiona guesses that the coin is likely to land in the blue area. which explains whether or not fiona is correct and why?

I'll give brainliest if you answer right : )

Yo need asap pls ! markin da brainiest too !