What is the constant of proportional

What is the value of the expression below? (81^2)^1/8

Which statement about perfect cubes is true

For which of the following counts would a binomial probability model not be reasonable? a)the number of people in a classroom born in januaryb) the number of people in a classroom with red hair c) the number of people admitted to a hospital in a day with a particular disease d) the number of heart beats in a one-minute perio.