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![Online Geometry Tutoring, Tutorial, Tutor](h_triangle_center_910.jpg)
Geometry Tutoring, Tutorial, Tutor: Triangle Centers, Theorems and Problems
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Triangle Centers - Table of
Content
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![The School of Athens](../euclid_teaching_geometry.jpg) |
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![Triangle centers, visual index](triangle_center_visual_inde.jpg) |
Triangle
Centers, Visual Index. |
![Incenter, Incircle, Index](incenter_incircle_17.jpg) |
Incenter of a triangle. Index.
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![Excenter, Excircle, Index](excenter_excircle_17.jpg) |
Excenter. Index.
Excircle, Exradius.
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![Circumcenter Index](circumcenter_index_17.jpg) |
Circumcenter. Index.
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![Centroid of a triangle Index](centroid_barycenter_index.jpg) |
Centroid /Barycenter. Index.
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![Orthocenter Index](orthocenter_altitude_index.jpg) |
Orthocenter
Index.
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![Orthocenter visual Index](orthocenter_theorems_problems_visual_index_software-1.jpg) |
Orthocenter of a triangle, Theorems and Problems - Visual Index. |
![Circumcircle Index](circumcircle_index_1.jpg) |
Circumcircle
Index.
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![Nine-point-circle, Euler Line, HTML5 Animation for iPad and Nexus](../center/nine_point_center_euler_html5_animation_ipad_nexus_1.jpg) |
Nine-Point Center, Nine-Point Circle, Euler Line.
Interactive illustration.
Circumcenter, Centroid, Orthocenter
HTML5 Animation for iPad and Nexus
Adobe Flash Animation.
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![Gergonne Point Theorems and Problems Index](../geometry/gergonne_point_index_1.jpg) |
Gergonne Points
Index
Triangle Center |
![Nagel Point Theorems and Problems Index](../geometry/nagel_point_index_1.jpg) |
Nagel Points
Index
Triangle Center |
![Lester Circle Theorem](../circle/lester-circle-fermat-circumcenter-nine-point-college-1.jpg) |
Lester Circle Theorem.
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![Gergonne Point Theorem](../center/gergonne-point-theorem-html5-ipad-nexus-1.jpg) |
Gergonne Point Theorem. Concurrency.
Interactive proof with animation.
HTML5 Animation for Tablets (iPad, Nexus)
Adobe Flash Animation
Key concept: Ceva's Theorem. |
![](../NagelPoint170.jpg) |
Nagel Point
Theorem. Proof.
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![](lemoine_point_170.jpg) |
Symmedian (Lemoine) Point
Triangle Center |
![Geometry Problem 1502](../school-college/6/p1502-rigth-triangle-incircles-measurement-inradius-square-quadrilateral-1.jpg) |
Geometry
Problem 1502.
Right Triangle, Incircle, Inradius, Geometric Mean of 2 Inradii, Angle Bisector, Perpendicular, Tangential Quadrilateral. |
![Geometry Problem 1492](../school-college/5/p1492-right-triangle-altitude-incenter-angle-measurement-1.gif) |
Geometry
Problem 1492.
Right Triangle, Altitude, Incenters, Angle, Measurement. |
![Geometry Problem 1491](../school-college/5/p1491-cyclic-quadrilateral-diagonal-incircle-angle-measurement-1.gif) |
Geometry
Problem 1491.
Cyclic Quadrilateral, Diagonal, Incircle, Angle, Measurement. |
![Geometry Problem 1490](../school-college/5/p1490-triangle-cevian-incircle-tangent-measurement-1.gif) |
Geometry
Problem 1490.
Triangle, Cevian, Incircle, Tangent, Measurement. |
![Geometry Problem 1489](../school-college/5/p1489-right-triangle-angle-bisector-perpendicular-measurement-1.gif) |
Geometry
Problem 1489.
Right Triangle, Angle Bisectors, Perpendicular, Measurement. |
![Geometry Problem 1488](../school-college/5/p1488-right-triangle-altitude-angle-bisector-measurement-1.gif) |
Geometry
Problem 1488.
Right Triangle, Altitude, Incircle, Tangent, Measurement. |
![Geometry Problem 1487](../school-college/5/p1487-right-triangle-altitude-angle-bisector-measurement-1.gif) |
Geometry
Problem 1487.
Right Triangle, Altitude, Incircle, Tangent, Measurement. |
![Geometry Problem 1486](../school-college/5/p1486-right-tringle-altitude-incircle-tangent-measurement-1.jpg) |
Geometry
Problem 1486.
Right Triangle, Altitude, Incircle, Tangent, Measurement. |
![Geometry Problem 1485](../school-college/5/p1485-triangle-altitude-orthocenter-circle-tangent-measurement-1.jpg) |
Geometry
Problem 1485.
Triangle, Orthocenter, Altitude, Circle, Diameter, Tangent, Measurement. |
![Dynamic Geometry 1480](../school-college/5/p1480-cyclic-polygon-triangulation-sum-inradii-invariant-geogebra-ipad-1.jpg) |
Dynamic Geometry 1480.
Japanese Theorem for Cyclic Polygon, Sangaku, Triangulation, Non-intersecting Diagonals, Sum of Inradii, Invariant, Step-by-step Illustration. GeoGebra,
iPad. |
![Dynamic Geometry 1479](../school-college/5/p1479-triangle-circumcircle-angle-perpendicular-bisector-parallel-concyclic-geogebra-ipad-1.jpg) |
Dynamic Geometry 1479.
Triangle, Circumcircle, Angle Bisector,
Perpendicular Bisector, Chord, Concyclic Points, Parallel Lines,, Step-by-step Illustration. GeoGebra,
iPad. |
![Dynamic Geometry 1478](../school-college/5/p1478-reuschle-terquem-theorem-3-cevians-circumcircle-concurrent-geogebra-ipad-1.jpg) |
Dynamic Geometry 1478.
Cyclocevian, Reuschle-Terquem Theorem, Concurrent Cevians, Triangle, Circumcircle, Secant line, Step-by-step Illustration. GeoGebra,
iPad. |
![Dynamic Geometry 1477](../school-college/5/p1477-miquel-pentagram-theorem-circumcircle-5-concyclic-geogebra-ipad-1.jpg) |
Dynamic Geometry 1477.
Miquel's Pentagram Theorem, Pentagon, Triangle, Circumcircles, Concyclic Points, Step-by-step Illustration. GeoGebra,
iPad. |
![Dynamic Geometry 1473](../school-college/5/p1473-kosnita-theorem-triangle-circumcenter-concurrent-geogebra-1.jpg) |
Dynamic Geometry 1473.
Kosnita's Theorem, Triangle, Four Circumcenters, Concurrent Line, Step-by-step Illustration. |
![Dynamic Geometry 1471](../school-college/5/p1471-equilateral-triangle-incenter-concurrent-geogebra-ipad-1.jpg) |
Dynamic Geometry 1471.
Equilateral Triangle, Inside/Outside Point, Incenters, Tangency Points, Concurrent Lines, Step-by-step Illustration. |
![Dynamic Geometry 1469](../school-college/5/p1469-triangle-inradius-circumradius-midpoint-geogebra-1.jpg) |
Dynamic Geometry 1469.
Triangle, Circumradius, Inradius, Midpoints, Arcs, Sum of Distances, Step-by-step Illustration. |
![Dynamic Geometry 1468](../school-college/5/p1468-steiner-theorem-triangle-inradius-exradius-circumradius-ipad-geogebra-1.jpg) |
Dynamic Geometry 1468.
Steiner's Theorem, Triangle, Circumradius, Inradius, Sum of Exradii, Step-by-step Illustration. |
![Geometry Problem 1458](../school-college/5/p1458-incircle-excircle-triangle-area-1.jpg) |
Geometry
Problem 1458.
Triangle, Incircles, Excircle, Area, Step-by-step Illustration using GeoGebra. |
![Geometry Problem 1457](../school-college/5/p1457-orthocenter-triangle-similarity-circles-radii-1.jpg) |
Geometry
Problem 1457.
Altitudes, Circles, Similarity,
Product of the Inradii Lengths,
iPad. Step-by-step illustration using GeoGebra. |
![Geometry Problem 1456](../school-college/5/p1456-orthocenter-triangle-similarity-circles-geogebra-ipad-1.jpg) |
Geometry
Problem 1456.
Altitudes, Orthic Triangle, Circumcircle, Parallel lines, Similarity, Area,
iPad. Step-by-step illustration using GeoGebra. |
![Geometry Problem 1455](../school-college/5/p1455-nagel-point-incircle-congruence-geogebra-ipad-1.jpg) |
Geometry
Problem 1455.
Nagel Point, Excircles, Incircle, Congruent Segments,
iPad. Step-by-step illustration using GeoGebra. |
![Fermat Point](../center/fermat_point_1.jpg) |
Geometry Problem 903: First Fermat Point.
Post a solution
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![Exeter Point](exeter-point-triangle-centroid-circumcircle-concurrency-euler-puzzle-1.jpg) |
Puzzle: Exeter Point Triangle, Median, Circumcircle, Concurrent Lines, Euler Line.
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![Exeter Point](exeter-point-triangle-centroid-circumcircle-concurrency-euler-html5-1.jpg) |
Dynamic Geometry: Exeter Point Triangle, Median, Circumcircle, Concurrent Lines, Euler Line, GeoGebra, HTML5 Animation for Tablets.
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![Second Fermat Point](fermat-point-second-dynamic-triangle-equilateral-1.jpg) |
Second Fermat Point: Static diagram.
Second Fermat Point: Dynamic diagram.
Triangle, Equilateral triangles, Concurrent lines, GeoGebra, HTML5 Animation for Tablets (iPad, Nexus) |
![Vecten Point](vecten_point_1.jpg) |
Outer Vecten Point.
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![Morley Triangle and Center](../geometry/morley_triangle_center_17.jpg) |
Morley's Triangle and Center
Triangle Center |
![Feuerbach Point](feuerbach_point_facts_170.jpg) |
Feuerbach
Point
Triangle Center |
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iPad Apps: Apollonius Software. Feuerbach Point. Triangle, Incircle, Nine point circle, Tangent circles, Orthocenter, Midpoint.
Interactive Geometry Software. |
![Schiffler Point](../geometry/schiffler_point_euler_17.jpg) |
Schiffler Point: Euler Lines
Triangle Center |
![](../Bevan170.jpg) |
The Bevan Point
The
circumcenter of the excentral triangle. Illustration with animation.
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![Spieker Center](spieker_center_170.jpg) |
Spieker Center
Triangle Center |
![Ajima Malfatti Point 2](ajima_malfatti_170_2.jpg) |
Ajima-Malfatti Point
2
Triangle Center.
Interactive illustration. |
![Ajima-Malfatti Point 1](ajima_malfatti_170.jpg) |
Ajima-Malfatti Point
1
Triangle Center.
Interactive illustration. |
![Steiner Point](steiner_point_170.jpg) |
Steiner Point
Triangle Center |
![Mittenpunkt Point](mittenpunk_point_170.jpg) |
Mittenpunkt
Point
Triangle Center |
![Kosnita theorem](kosnita_theorem_17.jpg) |
Kosnita's Theorem.
Circumcenters, Concurrent lines. |
![Clawson Point](clawson_point_triangle_1.jpg) |
Clawson Point.
Orthic and Extangents Triangles, Concurrent lines. |
![Clawson Point Puzzle, Geometry for Kids](clawson_point_puzzle_1.jpg) |
Clawson Point Puzzle, Geometry for Kids.
22 Piece Polygons |
![](../circle/adams_circle_theorem_170.jpg) |
Adams' Circle
Theorem
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![Distance between triangle centers](distance_triangle_centers.jpg) |
Distances between Triangle Centers
Index.
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![](../triangle_center_170.jpg) |
Triangle Centers. |
![Napoleon Theorem I](../problem/p246_napoleon_theorem_17.jpg) |
Proposed Problem 246.
Napoleon's Theorem I. External Equilateral triangles. |
![Circulo de los nueve puntos, Spanish](circulo_nueve_puntos_spanish.jpg) |
Circulo de los Nueve Puntos: Spanish version.
Interactive illustration.
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![](../puzzle/euler_line_nine_point_170.jpg) |
Puzzle: Euler Line and Nine Point Center
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![Problem 1447](../school-college/5/p1447-vecten-point-outer-geogebra-dynamic-1.jpg) |
Dynamic Geometry Problem 1447.
Outer Vecten Point. Step-by-step
illustration using GeoGebra. |
![Geometry problem 1231](../school-college/3/p1231-triangle-orthocenter-circumcenter-incenter-bisector-1.jpg) |
Geometry Problem 1231
Triangle, Orthocenter, Incenter, Circumcenter, Angle Bisector, Center, Circle. |
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