This is the last section of my class and I just don't get it. I can't even get my calculator so graph it for me (probably my stupid though). Can anyone please explain how to answer this type of question? I have 5 questions on the length of a parametric curve to do. I just can't understand what the book is saying (again probably my stupid). Any help is greatly appreciated.

If f(θ) is given by: f(θ)=18cos3θ and g(θ) is given by: g(θ)=18sin3θ

Find the total length of the astroid described by f(θ) and g(θ).

(The astroid is the curve swept out by (f(θ),g(θ)) as θ ranges from 0 to 2π. )