1. Constructors
2. new
3. Properties
4. area
5. averageRadius
6. center
7. hashCode
8. innerCircumference
9. innerRadius
10. outerCircumference
11. outerRadius
12. runtimeType
13. width
14. Methods
15. contains
16. noSuchMethod
17. scale
18. toString
19. translate
20. Operators
21. operator ==