Online Geometry

Online Geometry: Triangle Centers, Theorems and Problems Index, Page 2

Triangle Centers - Table of Content 2

The School of Athens

 

Adams Circle

Geometry Problem 821.
Adams Circle.

Equilateral triangle, Perimeter

Geometry Problem 754.
Equilateral Triangle, Center, Angle, 60 Degrees, Perimeter.

Distance between the incenter to the centroid

Problem 690: Distance between the Incenter and the Centroid of a Triangle.
Formula in terms of the sides a,b,c.

Triangle, Excircles, Tangent, Concurrency

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

Triangle with squares, Circumcircles

Proposed Problem 370.
Triangle with squares, Circumcircles, Tangent circles.

Equal Incircles Theorem: Triangles, cevians, circles.

Problem 257: Equilateral triangle, circumcircle

Proposed Problem 257.
Equilateral Triangle, Circumcircle, Point, Vertices, Side, Distances, Squares.

Elearning 256: Equilateral triangle

Proposed Problem 256.
Equilateral Triangle, Circumcircle, Point, Vertices, Distances.

Problem 254: Triangle and Centroid

Proposed Problem 255.
Triangle, Centroid, Vertices, a Point, Distances, Squares.

Elearning 254: Triangle and Centroid

Proposed Problem 254.
Triangle, Centroid, Vertices, a Point, Distances, Squares.

Elearning 253: Triangle, Centroid

Proposed Problem 253.
Triangle, Centroid, Vertices, Distances, Squares.

Triangle sides, medians, squares

Proposed Problem 249.
Triangle sides, medians, squares.

Elearning: Napoleon Theorem III

Proposed Problem 248.
Napoleon's Theorem III. Inner and outer Napoleon triangles, Area.

Napoleon Theorem II

Proposed Problem 247.
Napoleon's Theorem II. Internal Equilateral triangles. Inner Napoleon triangle.

Elearn 229: Triangle, Centroid, Transversal

Proposed Problem 229. Triangle, Centroid, Transversal, Perpendicular lines.

Problem 226: Triangle, Centroid

Proposed Problem 226. Triangle, Centroid, Perpendicular lines.  

Right triangle, inradius, altitude, arithmetic mean

Proposed Problem 220. Right Triangle, Altitude, Angle Bisector, Distance, Arithmetic Mean.  

Elearn: Quadrilateral, Angle Bisectors, Concurrency

Proposed Problem 216. Quadrilateral, Angle Bisectors, and Concurrency.

Elearning 196: Inradius, Exradii

Proposed Problem 196. Triangle, Inradius and Exradii Formula.

Elearn 213 Triangle Inradius, Common Tangents

Proposed Problem 213. Triangle, Incircle, Inradius, Semicircles, Common Tangents.

Elearn 209

Proposed Problem 209. Triangle, Incircles, Inradius.

Elearn 208: Triangle, Angles

Proposed Problem 208. Triangle, Excircles, Angles, 360 degrees.  

Problem 207: Hypotenuse

Proposed Problem 207. Right Triangle, Hypotenuse, Inradius, Exradius relative to the hypotenuse.  

Elearn 206

Problem 206. Area of a Right Triangle, Inradius, andExradius relative to the hypotenuse.  

Right triangle area

Proposed Problem 205. Right Triangle Area, Exradii relatives to legs or catheti.  

Elearn 204

Proposed Problem 204. Right Triangle, Incircle, Excircles, Inradius, Exradii.  

Problem 203

Proposed Problem 203. Right Triangle, Excircles, Exradii, Hypotenuse.  

Problem 202 Right triangle, excircles

Proposed Problem 202. Right Triangle, Incicrle, Excircles relatives to catheti, Points of Tangency, Exradius, Semiperimeter.  

Elearn 201

Proposed Problem 201. Right Triangle, Excircles, Points of Tangency, Exradius, Semiperimeter.  

Elearning 200: Right Triangle

Proposed Problem 200. RightTriangle, Incircle, Excircles, Points of Tangency, Inradius.

Elearning 197: Triangle Area

Proposed Problem 197. Area of a Triangle, Side, Inradius, and Exradius.

Elearning 196: Inradius, Exradii

Proposed Problem 196. Triangle, Inradius and Exradii Formula.

Geometry: Triangle Area, inradius, exradii

Proposed Problem 195. Area of a Triangle, Inradius, Exradii.

Area of a triangle, semiperimeter, exradius

Proposed Problem 194. Area of a Triangle, Semiperimeter, Exradius.

Area of a triangle, semiperimeter, inradius

Proposed Problem 193. Area of a Triangle, Semiperimeter, Inradius.

Geometry Problem 191 about triangle and squares

Proposed Problem 191. Triangle, Altitudes, Orthocenter, Squares, Areas.  

Puzzle of the Nagel Point: 22 pieces of polygons.

Nagel Point Theorem - Flowchart Proof .
 

Semiperimeter and excircles of a triangle.

 

Semiperimeter and incircle of a triangle.

Semiperimeter, incircle and excircles of a triangle.

 

Gergonne Point Theorem

Gergonne Point Theorem. Concurrency. Interactive proof with animation.

Key concept: Ceva's Theorem.
 

Elearning 187: Right triangle, incircles, angles

Proposed Problem 187. Right Triangle, Altitude, Incenters, Circles, Angles.  

Elearning 186: Right triangle, circles

Proposed Problem 186. Right Triangle, Altitude, Incenters, Circles.  

Elearning 186: Right triangle, circles

Proposed Problem 186. Right Triangle, Altitude, Incenters, Circles.  

Elearning: Triangle, Circle, Incircle, Radius

Proposed Problem 160. Triangle, Incircle, Incenter, Circumcircle, Circumcenter, Inradius.  

Triangle Elearning 159

Proposed Problem 159. Distances from the Circumcenter to the Incenter and the Excenters.  

Geometry Problem 158

Proposed Problem 158. Relation between the Circumradius, Inradius and Exradii of a triangle.  

Elearning triangle 157

Proposed Problem 157. Distance from the Circumcenter to the Excenter.  

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Last updated: Mar 9, 2022