Circles: Table of Content




76. 

Feuerbach
Theorem
One of the most striking theorems in triangle geometry. 
75. 

Feuerbach
Point Facts

74. 

Feuerbach
Theorem, Acute Triangle
illustration

73. 

Feuerbach
Theorem,
Obtuse Triangle illustration

72. 

Hippocrates and Squaring the Circle

71. 

Lunes of
Hippocrates 4

70. 

Lunes of
Hippocrates 3

69. 

Lunes of
Hippocrates 2

68. 

Lunes
of Hippocrates 1

67. 

Pythagoras and Circle Area

66. 

Brahmagupta's Theorem
Cyclic quadrilateral.

65. 

Brahmagupta's Corollary
Cyclic quadrilateral.

64. 

Brahmagupta's Formula
Area of a cyclic quadrilateral.

63. 

Mascheroni Construction with compass
alone. Midpoint of a segment

62. 

Sangaku Proposed
Problem 41. "Mickey Mouse."
Three circles, tangents, radii. 
61. 

NinePoint Center,
NinePoint Circle, Euler Line.
Interactive illustration.

60. 

Lemoine Theorem

59. 

Second AjimaMalfatti Point
Interactive illustration. 
58. 

First AjimaMalfatti Point
Animated illustration. 
57. 

Proposed
Problem 39.
Triangle, Incircle, Bisector, Cyclic Quadrilateral and angles. 
56. 

Proposed
Problem 39 Geometry Help.
Facts you should know for the proposed problem 39. 
55. 

Proposed Problem 38.
Right
Triangle, altitude, incircles, incenters, and angles. 
54. 

Proposed Problem 35.
Incenters and Inradii in Cyclic Quadrilateral. 
53. 

Sawayama Thebault's
theorem 
52. 

Proposed Problem 34.
Right
triangle, cevian, incircles, tangents and inradius. 
51. 

Apollonius' Problem for Three Circles
Illustration with animation and sound.
