Answer:
The given expression is a cubic polynomial with degree 3.
Step-by-step explanation:
We are given the following in the question:

Polynomial:
- A polynomial is an expression.
- It consisting of variables and coefficients.
- The variables and coefficients involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.
Since, the given expression satisfies all the properties, it is a polynomial.
Degree of polynomial:
- It is the maximum degree of the polynomial.
The degree of given polynomial is 3.
Nature of polynomial:
It is a cubic polynomial.
Are you asking how to solve this equation?
answer:
131.88 inches
step-by-step explanation:
- know the formula: 2πr
- now plug in what we have
2πr = circumference
2(21)(3.14)
= 131.88