Which of the following are irrational numbers? a. pie (the number lol) b. 4.8 repeating c. square root of 9 d. all of the above

is the only irrational number on the list. As a reminder, an irrational number is one which can't be written as a ratio of two integers.

With a little scratch work, we can show that can be written this way:

And , which can be written as a ratio like , or any other where the numerator is 3 times larger than the denominator.

A proof of the irrationality of is pretty involved and advanced, so you'll just have to take my word for it for now!