Geometry: Nagel Points,
Theorems and Problems  Table of
Content




Nagel Point
Theorem.
Concurrency. Interactive proof with Flash animation proof. 

Puzzle of the Nagel
Point: 22 pieces of polygons. 

Nagel
Point Theorem  Flowchart Proof .


Geometry
Problem 1455.
Nagel Point, Excircles, Incircle, Congruent Segments,
iPad. Stepbystep illustration using GeoGebra. 

Geometry Problem 689.
Triangle, Three Excircles, Tangency points, Tangent lines, Concurrent Lines, Mind Map. 

Geometry Problem 687.
Triangle, Three Excircles, Tangency points, Concurrent Lines. 

Geometry Problem 684:
Outer Nagel Point.
Triangle, Excircles, Incircle Tangency points, Concurrent lines, Semiperimeter, Ceva theorem. 

Geometry Problem 683:
Nagel Point.
Triangle, Excircles, Tangency points, Concurrent lines, Semiperimeter, Ceva theorem. 

Geometry Problem 138. Nagel's
Theorem, Orthic Triangle, Altitudes, Circumradius, Perpendicular. 

Gergonne Point Theorem. Concurrency.
Interactive proof with animation.
Key concept: Ceva's Theorem. 

Semiperimeter and excircles of a triangle.


Semiperimeter and incircle of a triangle. 

Semiperimeter, incircle and excircles of a triangle.
