Triangle Centers  Table of
Content 2




Geometry Problem 821.
Adams Circle. 

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

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

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

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

Equal Incircles Theorem: Triangles,
cevians, circles. 

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


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


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


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


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


Proposed Problem 249.
Triangle sides, medians, squares.


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


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


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

Proposed Problem 226. Triangle, Centroid, Perpendicular lines.


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


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


Proposed Problem 196. Triangle,
Inradius and Exradii Formula. 

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

Proposed Problem 209. Triangle, Incircles, Inradius. 

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


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

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

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

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

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

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

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


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

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

Proposed Problem 196. Triangle,
Inradius and Exradii Formula. 

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

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

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

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


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

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

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

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

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

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

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