Japanese Theorem for Cyclic Polygons

Japanese Theorem for Cyclic Polygons
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2016-01-24 00:52
This example illustrates the Japanese Theorem for cyclic polygons, which states that the sum of the radii of the incircles of a cyclic polygon is a constant. Key concepts include polygons, incircles, and geometric construction. Commands used include Vector, Circle, Point, Polygon, Translate, Segment, and Incenter. Suitable for high school mathematics education and learning.

GeoGebra Commands & Parameters

  1. Vector(P, Q) → u
  2. Circle(O, 1) → c
  3. Point(c) → A
  4. Point(c) → B
  5. Point(c) → C
  6. Point(c) → D
  7. Point(c) → E
  8. Polygon(A, B, C, D, E) → poly1, a, b, c_1, d, e
  9. Translate(A, u) → A'
  10. Translate(B, u) → B'
  11. Translate(C, u) → C'
  12. Translate(D, u) → D'
  13. Translate(E, u) → E'
  14. Polygon(A', B', C', D', E') → poly1', a', b', c', d', e'
  15. Translate(A', u) → A''
  16. Translate(B', u) → B''
  17. Translate(C', u) → C''
  18. Translate(D', u) → D''
  19. Translate(E', u) → E''
  20. Polygon(A'', B'', C'', D'', E'') → poly1'', a'', b'', c'', d'', e''
  21. Translate(A'', u) → A'''
  22. Translate(B'', u) → B'''
  23. Translate(C'', u) → C'''
  24. Translate(D'', u) → D'''
  25. Translate(E'', u) → E'''
  26. Polygon(A''', B''', C''', D''', E''') → poly1''', a''', b''', c''', d''', e'''
  27. Translate(A''', u) → F
  28. Translate(B''', u) → G
  29. Translate(C''', u) → H
  30. Translate(D''', u) → I
  31. Translate(E''', u) → J
  32. Polygon(F, G, H, I, J) → poly2, f, g, h, i, j
  33. Segment(A, D) → k
  34. Segment(A, C) → l
  35. Segment(B', E') → m
  36. Segment(B', D') → n
  37. Segment(C'', A'') → p
  38. Segment(C'', E'') → q
  39. Segment(D''', B''') → r
  40. Segment(D''', A''') → s
  41. Segment(J, H) → t
  42. Segment(J, G) → a_1
  43. Incenter(A, B, C) → d_1, b_1, K, L
  44. Incenter(A, C, D) → e_1, f_1, M, N
  45. Incenter(A, D, E) → g_1, h_1, R, S
  46. Incenter(A', E', B') → k_1, i_1, T, U
  47. Incenter(E', D', B') → p_1, j_1, V, W
  48. Incenter(B', D', C') → q_1, l_1, Z, A_1
  49. Incenter(C'', A'', B'') → r_1, m_1, B_1, C_1
  50. Incenter(C'', E'', A'') → s_1, n_1, D_1, E_1
  51. Incenter(C'', D'', E'') → t_1, a_2, F_1, G_1
  52. Incenter(D''', E''', A''') → c_2, b_2, H_1, I_1
  53. Incenter(D''', A''', B''') → d_2, e_2, J_1, K_1
  54. Incenter(D''', B''', C''') → f_2, g_2, L_1, M_1
  55. Incenter(J, G, F) → h_2, i_2, N_1, O_1
  56. Incenter(J, H, G) → k_2, j_2, P_1, Q_1
  57. Incenter(J, I, H) → p_2, l_2, R_1, S_1

AI Drawing Prompt Reference

Draw a cyclic pentagon where the sum of the radii of the incircles is constant. Start by placing five points A, B, C, D, and E on a circle and connecting them to form a pentagon. Then translate each point three times along vector u to form a new pentagon. Next, connect corresponding vertices of the original and translated pentagons, and connect adjacent vertices of the original pentagon. Finally, find the incenter of each triangle formed by the original pentagon, which will form a new pentagon.
The prompt above was compiled from the original drawing commands and is for reference only.