Geometry - Table of Content

Problems.

Geometry Videos Index

Definitions.

Points, Theorems and Problems - Index.

Angles. Theorems and Problems.

Angle Bisector. Theorems and Problems.

Acute Angle in the Real World - Slideshow.

Obtuse Angle. Theorems and Problems.

Angles: 30, 60, 120 degrees.

Angles: 45, 135 degrees.

Parallel lines.

Perpendicular lines.

Perpendicular Bisector.

Concurrent lines.

Transversal Lines.

Collinear Points.
Theorems and Problems

Midpoints.
Theorems and Problems

Triangles.

Equilateral Triangles.

Isosceles Triangle.

Isosceles Triangle 80-20-80.

Right Triangle.

Special Right Triangles.

Special Right Triangle 30-60.

Metric Relations in a Right Triangle, Theorems and Problems.

Obtuse Triangle.

Altitude Index.
Theorems and Problems.

Median Index.
Theorems and Problems.

Semiperimeter, Perimeter Index.
Theorems and Problems.

Heron's Formula.
Key facts and a purely geometric step-by-step proof.
 

Triangle and Squares.

Quadrilaterals.

Parallelograms Index.

Square.

Rectangle.

Rhombus.

Trapezoids.

Median of a Trapezoid, Theorems and Problems. Index.

Cyclic Quadrilateral.
 

Ptolemy's Theorems and Problems - Index.

Brahmagupta Theorem and Problems - Index
Brahmagupta (598–668) was an Indian mathematician and astronomer who discovered a neat formula for the area of a cyclic quadrilateral.

Tangential or Circumscribed Quadrilateral
 

Equilic Quadrilateral.
 

Complete Quadrilateral Index.
 

Polygons.

Pentagons.

Hexagons.

Heptagons.

Octagons.

Nonagon or Enneagon.

Circles.

Circular Sector. Index.
Theorems and Problems. 

Arbelos, Theorems and Problems
Three tangent semicircles with collinear centers.
Index 

Archimedes' Book of Lemmas
 

Lunes of Hippocrates
 

Intersecting Circles Index.
Theorems and Problems.

Tangent Circles Index
 

Intersection of a Line with a Circle
 

Pi Day.
Saturday, March 14, 2009 = 3.14
It's time to get irrational. Tomorrow is Pi Day, when mathematicians will gather to celebrate the mystery of science's most famous strange number.

Mascheroni construction with compass alone. Index

Triangle Centers.

Centroid /Barycenter. Index.

Circumcenter. Index.

Incenter. Index.

Excenter. Index.
Excircle, Exradius.

Orthocenter. Index.

Circumcircle Index.

Distances between Triangle Centers Index.

Congruence. Index.
 

Similarity, Ratios, Proportions. Index.

Areas Index.

Area of a Triangle Index.

Area of a Square Index.

Classical Theorems.

Solid Geometry.

Geometric Mean.

Complete List of Go Geometry Problems.
Go Geometry Problems.

Geometry Problems - Visual Index.

Ten Geometry Problems, Visual Index

Geometry Problems Gallery Index
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57.

Geometria en Espanol, Teoremas y Problemas en Espanol.
(Spanish-language version)

Problemas Propuestos de Geometria en Espanol.

Archimedes. 

Fractal Geometry Index.

Hyperbolic Geometry Index.

Computational Geometry - Index

Discrete Differential Geometry Index

Topology - Index

Polyomino Word Cloud and News.

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

Euclidean Geometry Selections.

Crop Circles and Complexity
Crop Circles and Sacred Geometry
 

Sacred Geometry.

Geometry Word Cloud Index.

Tessellations.

The Geometry of Sprawl: Sun City, AZ, Geometric Sociology - Map and News.

Kaleidoscopes Index.  

Geometry Projects Brainstorming.

Geometric Art.

Great Paintings - Index

Geometry for Children.

Geometry in the Real World - Index.

Sangaku Japanese Geometry.
Seventeenth and nineteenth centuries.

Montessori Method - Index.
The Montessori method is an approach to educating children based on the research and experiences of Italian physician and educator Maria Montessori (1870–1952).

Montessori Students: Google Founders Experience - Video and News.
Larry Page and Sergey Brin discuss their experience as Montessori students.

Steiner-Waldorf Education Index.

Saturn and Geometry Index.

Software Index.

Dynamic Geometry.

Dynamic Geometry Software: GeoGebra 3.2 Help Document
GeoGebra is a dynamic geometry software. Constructions can be made with points, vectors, segments, lines, polygons, conic sections, and functions.
Interactive Mind Map

Geometry Expressions.

TracenPoche Interactive Geometry Software Applications.

iPad Apps, Index.

Wolfram Mathematica Software.

Wolfram Demonstrations Project & GoGeometry.
Interact with demonstrations using the free Mathematica Player

Wolfram Alpha Examples, Mathematics, Geometry, Interactive Mind Map.

Surfing: Tube Wave,
Index.

Geometry Mind Mapping - Index

SAT Math Practice,
Index.

Golden Rectangles.

Go Geometry Education Index

Van Hiele Model Index
In mathematics education, the Van Hiele model is a theory that describes how students learn geometry.

Explore the Geometry of the Human Anatomy.

Geometry Online - Table of Content