Rectangle, Theorems and Problems - Table of Content

Euclid's Elements, Book X, Lemma for Proposition 33 One page visual illustration.

Proposed Problem 252.
Rectangle, isosceles right triangle, square, areas.

Eyeball Theorem: Animated Angle to Geometry Study.
Chords and Rectangle.

Eight-Point Circle Theorem
Step-by-Step construction, Manipulation, and animation.
Mindpoints and Rectangle

Sangaku Problem. The incenters of four triangles in a cyclic quadrilateral form a rectangle.

Cyclic Quadrilateral: Ratio of the Diagonals
The ratio of the diagonals of any cyclic quadrilateral equals the ratio of the sums of the rectangles contained by the sides that share the diagonals' end points 

SAT Math Practice 1,
Video.

Area of a Square Index.

Interactive Mind Map of the Van Hiele Model of Geometric Thought
Level 2. Abstraction: learners recognize relationships between types of shapes. They recognize that all squares are rectangles, but not all rectangles are squares.  

Triangle and Squares 22
Rectangles of equal area. 

Triangle and Squares 20
Rectangles of equal area. 

Parallelograms Index.

Composition II in Red, Blue, and Yellow by Piet Mondrian, pioneer of Geometric abstraction.

Hippocrates and Squaring the Circle
 

Thébault's Theorem. Parallelogram with Squares theorem
 

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

Proposed Problem 35.
Rectangle, Incenters and Inradii in Cyclic Quadrilateral.

Golden Rectangles Index.

Arithmetic Composition, 1929-1930 by Theo van Doesburg, pioneer of Geometric abstraction.

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

Interactive Geometry Glossary using AnswerTips technology.
Rectangle.

Polygon Classification. Interactive Mind Map.