Regular Nonagon Inner Angles and Construction

GeoGebra Commands & Parameters

1. Polygon(A, B, 9) → poly1, a, C, D, E, F, G, H, I, b, c, d, e, f, g, h, i
2. Rotate(B, 70*°, A) → B'
3. Angle(B, A, B') → α
4. Rotate(A, -70*°, B) → A'
5. Angle(A', B, A) → β
6. Ray(A, B') → j
7. Ray(B, A') → k
8. Intersect(j, k) → J
9. Segment(J, C) → l
10. Segment(J, D) → m
11. Segment(E, J) → n
12. Segment(F, J) → p
13. Segment(J, G) → q
14. Segment(H, J) → r
15. Segment(J, I) → s
16. Segment(J, B) → t
17. Segment(J, A) → a_1
18. Angle(A, J, B) → γ
19. Angle(B, J, C) → δ
20. Angle(C, B, J) → ε
21. Angle(J, C, B) → ζ
22. Angle(J, D, C) → η
23. Angle(C, J, D) → θ
24. Angle(D, C, J) → ι
25. Angle(J, E, D) → κ
26. Angle(E, D, J) → λ
27. Angle(D, J, E) → μ
28. Angle(E, J, F) → ν
29. Angle(J, F, E) → ξ
30. Angle(F, E, J) → ο
31. Angle(J, G, F) → ρ
32. Angle(G, F, J) → σ
33. Angle(F, J, G) → τ
34. Angle(J, H, G) → υ
35. Angle(H, G, J) → ϕ
36. Angle(G, J, H) → χ
37. Angle(J, I, H) → ψ
38. Angle(I, H, J) → ω
39. Angle(H, J, I) → α_1
40. Angle(A, I, J) → β_1
41. Angle(I, J, A) → γ_1
42. Angle(J, A, I) → δ_1
43. Polygon(F, E, J) → poly2, EF, f_1, e_1
44. Polygon(E, D, J) → poly3, DE, e_2, d_1
45. Polygon(D, C, J) → poly4, CD, d_2, c_1
46. Polygon(J, C, B) → poly5, b_1, BC, c_2
47. Polygon(J, B, A) → poly6, a_2, AB, b_2
48. Polygon(J, A, I) → poly7, i_1, IA, a_3
49. Polygon(J, I, H) → poly8, h_1, HI, i_2
50. Polygon(G, J, H) → poly9, h_2, g_1, GH
51. Polygon(F, G, J) → poly10, FG, f_2, g_2