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Geometry: Nagel Points, Theorems and Problems - Table of Content

Nagel Point Theorems and Problems Index

 

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

Geometry Problem 1455.
Nagel Point, Excircles, Incircle, Congruent Segments, iPad. Step-by-step illustration using GeoGebra.

Triangle, Excircles, Tangent, Concurrency

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

Triangle, Excircles, COncurrency

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

Outer Nagel Point

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

Nagel Point

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

Nagel Theorem

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

Gergonne Point Theorem

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.

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Last updated: Feb 29, 2020