Centroid of a triangle, Theorems and Problems - Table of Content

Euclid's Elements Book I, 23 Definitions. One-page visual illustration.
Euclid's Elements Book. Index

Triangle Centers.

Proposed Problem 402.
Hexagon, Triangle, Centroid, Parallel, Congruence, Similarity.

Proposed Problem 161.
Parallelogram, Midpoints, Octagon, Areas, Centroid.

Nine-Point Center, Nine-Point Circle, Euler Line (English version).
Interactive illustration.
Centroid, Orthocenter, Circumcenter.

Puzzle: Euler Line and Nine Point Center

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

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 246.
Napoleon's Theorem I. External Equilateral triangles.

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

Proposed Problem 227. Triangle, Centroid, Exterior line, Perpendicular lines.

Proposed Problem 226. Triangle, Centroid, Perpendicular lines.  

Journey to the Center of a Triangle (1976). Incenter, Circumcenter, Centroid, Orthocenter.

Eight-Point Circle Theorem centroid or gravity center of quadrilateral.
Step-by-Step construction, Manipulation, and animation.

Triangle, Medians, Six Circumcenters Concyclic. Dynamic Geometry.
Step-by-Step construction, Manipulation, and animation.
Prove proposition.

Proposed Problem 127. Centroid and Incenter of a Triangle, Parallel, Proportions.

Spieker Center Medial triangle, Centroid, Incircle

Heron's Formula with medians 

Symmedian (Lemoine) Point
Triangle Center

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

Right Triangle: Centroid. Centers, Inradius, Circumradius, Incenter, Circumcenter, Orthocenter, Centroid, Poncelet's theorem, Sagitta

Proposed Problem 98. Quadrilateral Area, Centroid, Similarity.