[racket] Math Guidance

To bring the discussion back on topic:
According to both the paper explaining the development of HtDP (PDF:
http://www.ccs.neu.edu/scheme/pubs/jfp2004-fffk.pdf ) and the course
in which it is used (Comp Sci I) the goal of HtDP is to introduce to
you the types of math/programming problems that you will encounter
throughout a CS program. I understand that it doesn't answer your
question and I also have not reached that chapter or exercise yet but
glancing at the exercise a basic knowledge of Pre/Calculus (at least
an understanding the sine and cosine functions and how to convert
radians to degrees) is expected. Afterwards, a usual progression in an
undergrad CS curriculum is Discrete Maths and Data
Structures/Algorithms (not strictly math though).