1. This is a nonagon. A nonagon is a 9-sided polygon; the figure has 9 sides.
2. This is not a regular polygon. A regular polygon is equiangular and equilateral which means that all of the angles are equal in measure and all of the sides are equal in length. The figure shown does not have equal sides or angles; therefore, it is an irregular polygon.
13.04 ( You just need to divide by 5 to find one fifth)
T = r