"Your math will improve dramatically with me"
...In particular, a polygon with many sides will have a perimeter very close to the perimeter of the circle which is 2*Pi*r. Perhaps the most difficult hurdle in pre-algebra is how to add, subtract, multiply, and divide fractions. Adding and subtracting fractions requires a common denominator. Multiplying fractions does not, and dividing by a fraction...
10+ subjects, including geometry