Collinear Points, Theorems and Problems - Table of Content

Points, Theorems and Problems - Index.

Lemoine Line Theorem, Interactive illustration.
HTML5 Animation for iPad and Nexus
Adobe Flash Animation

Nine-Point Center, Nine-Point Circle, Euler Line.
Interactive illustration.
Collinear Points.

Pappus Theorem. Dynamic Geometry.
Step-by-Step construction, Manipulation, and animation.
Collinear Points.

Interactive Gergonne Line and Nobbs Points. Dynamic Geometry.
Step-by-Step construction, Manipulation, and animation.
Collinear Points.

Interactive Simson Line. Dynamic Geometry.
Step-by-Step construction, Manipulation, and animation.
Collinear Points.

GeoGebra, Dynamic Geometry: Lemoine Line of a Triangle.
HTML5 Animation for Tablets (iPad, Nexus..)

GeoGebra, Dynamic Geometry: Simson Line of a Triangle.
HTML5 Animation for Tablets (iPad, Nexus..)

Sawayama -Thebault's theorem
Collinear Points.

Monge & d'Alembert Three Circles Theorem II with Dynamic Geometry. You can alter the geometric construction dynamically in order to test and prove (or disproved) conjectures and gain mathematical insight that is less readily available with static drawings by hand.
Collinear Points.

Monge & d'Alembert Three Circles Theorem I with Dynamic Geometry. You can alter the geometric construction dynamically in order to test and prove (or disproved) conjectures and gain mathematical insight that is less readily available with static drawings by hand.
Collinear Points.

Triangle with the bisectors of the exterior angles. Collinearity.
Key concept: Menelaus Theorem.
Collinear Points 

Complete Quadrilateral: Ortholine-Steiner Line.
Step-by-Step construction, Manipulation, and animation
Collinear Points.

Triangle and Squares Theorem 1: with Interactive Geometry Software
Step-by-Step construction, Manipulation, and animation.
Collinear Points.

Newton's Theorem, Newton-Gauss Line: Complete quadrilateral theorem. Using TracenPoche Dynamic Geometry Software, Online Step-by-Step construction, manipulation, and animation.
Collinear Points.

Schiffler Point: Four Euler Lines with interactive animation and manipulation.
Collinear Points.

Pascal's Mystic Hexagram Theorem Proof

Newton's Theorem: Newton's Line. Circumscribed quadrilateral, midpoints of diagonals, center of the circle inscribed.
Collinear Points.

Equilic Quadrilateral.
Collinear Points. 

Geometry Problem 870
Triangle, Median, Three Squares, Centers, Vertices, Collinear Points, Midpoint.

Geometry Problem 869
Triangle, Median, Three Equilateral Triangles, Collinear Points, Midpoint.

Geometry Problem 824
Desargues' Theorem, Triangles in Perspective.

Geometry Problem 723.
Squares, Circumscribed Circles, Collinear points.

Geometry Problem 722.
Squares, Circumscribed Circles, Collinear points.

Geometry Problem 721.
Triangle, Orthocenter, Circumcircle, Altitude, Collinear points.

Geometry Problem 710.
Parallelogram, Midpoint, Diagonal, Collinear Points, Metric Relations, Triangle, Similarity, Congruence.

Geometry Problem 678.
Triangle, Simson Line, Circumcircle, Tangent, Parallel, Perpendicular, Collinear Points.

Geometry Problem 675.
Intersecting Circles, Secant, 45 and 90 Degrees, Collinear Points.

Geometry Problem 669.
Triangle, Circumcircle, Incenter, Midpoint, Collinear points, Mind Map.

Geometry Problem 659.
Parallelogram, Parallel Lines, Collinear Points.

Geometry Problem 632.
Triangle, Interior and Exterior Angle Bisectors, Midpoints, Collinear Points.

Geometry Problem 631.
Triangle, Exterior Angle Bisectors, Collinear Points.

Geometry Problem 613
Altitude of a Triangle, Perpendicular, Collinear Points.

Geometry Problem 612
Altitude of a Triangle, Perpendicular, Congruence.

Geometry Problem 611
Altitude of a Triangle, Perpendicular, Collinear Points, Parallel.

Geometry Problem 609
Triangle, Perpendiculars, 90 Degrees, Collinearity.

Geometry Problem 593.
Triangle, Circumcircle, Collinear Points.

Problem 570.
Square, Center, Right Triangles, Congruence, Collinearity.

Problem 567.
Right triangle, Incircle, Excircle, Collinear tangency points.

Problem 523.
Tangent Circles, Diameter Perpendicular, Collinearity.

Problem 486.
Tangent circles, Chord, Arc, Midpoint, Collinearity, Congruence.

Proposed Problem 456.
Three tangent circles, Center, Chord, Secant, Collinear.

Proposed Problem 393.
Triangle, Orthocenter, Circumcircles, Congruence, Collinear.

Proposed Problem 392.
Triangle, Parallel lines, Concurrent lines.

Proposed Problem 391.
Triangle, Parallel lines, Collinear points.

Proposed Problem 390.
Triangle, Parallel lines, Collinear points.

Proposed Problem 323.
Triangle, Incenter, Circumcenter, Equal circles, Collinearity.

Proposed Problem 321.
Triangle, Incenter, Excircle, Midpoint of the Altitude, Collinearity.

Proposed Problem 320.
Triangle, Circumcircle, Incenter, Excenter, Collinear points.

Proposed Problem 318.
A Scalene triangle, Altitudes, Collinear points.

Proposed Problem 319.
Triangle, Altitudes, Perpendiculars, Collinear points.

Proposed Problem 133. Triangle, Interior and Exterior Angle Bisectors,
Collinear Points.

The Bevan Point The circumcenter of the excentral triangle. Illustration with animation.
Collinear Points.

Simson Line. A proof of Simson line with animation.

Geometry Online Glossary. Collinear Points.
Geometry Glossary based on the new New York State mathematics standards initiative.

Interactive Geometry Glossary using AnswerTips technology.
Nonagon or Enneagon.