Multiple choice How many irrational numbers are there: √2, √4, √(21/4), ∛27 zero one two more than two Reveal answer Fill a bubble to check yourself B Correct answer Explanation sqrt(2) is irrational. sqrt(4) = 2 (rational). sqrt(2 1/4) = sqrt(9/4) = 3/2 = 1.5 (rational). cbrt(27) = 3 (rational). Only one number is irrational.