Online Geometry: Rectangle, Theorems and Problems




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

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

EightPoint Circle Theorem
StepbyStep 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 

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.


Billiards and Geometry 
Index
Billiards Table 

Hippocrates and Squaring the Circle


Thébault's Theorem. Parallelogram with Squares theorem


Euclid's Elements
Book I, 23 Definitions. Onepage visual illustration.
Euclid's Elements Book.
Index 

Geometry Problem 1352. Rectangles, Sum of Squared Distances. 

Geometry Problem 1318.
Rectangle, Equilateral Triangle, Distances, Perpendicular, Measurement. 

Geometry Problem 1198
Right Triangle, Square, Rectangle, Quadrilateral, Altitude, Equal Areas. 

Geometry Problem 1195
Square, Two Rectangles, Congruence, Metric Relations. 

Geometry Problem 1185
Similar Rectangles, Four Quadrilaterals, Sum of the Areas, Metric Relations. 

Geometry Problem 1144.
Three Equal Squares, Diagonals, Perpendicular, 90 Degrees, Angle Bisector. 

Geometry Problem
1070.
Circle, Chord, Equilateral Triangle, Square, Rectangle, Area, Diameter, Perpendicular. 

Geometry Problem
1046.
Rectangle, Circle, Circumradius, Metric Relations. 

Geometry Problem 989.
Arbelos, Semicircles, Diameter, Perpendicular, 90 Degree, Common External Tangent, Rectangle, Midpoint of Arc. 

Geometry Problem 971.
Equilateral Triangle, Rectangle, Common Vertex, Sum of Right Triangles Areas. 

Geometry Problem 969.
Equilateral Triangle, Rectangle, Common Vertex, Right Triangles Areas. 

Geometry Problem 968.
Equilateral Triangle, Rectangle, Common Vertex, Midpoint. 

Geometry Problem 868
Cyclic Quadrilateral, Circle, Five Rectangles, Four Centers, Congruence. 

Geometry Problem
711.
Rectangle, Midpoint, Angle, Concyclic Points, Cyclic Quadrilateral. 

Geometry Problem 866
Cyclic Quadrilateral, Circle, Rectangle, Center, Congruence, 90 Degrees. 

Geometry Problem
620
Three Rectangles, Diagonals, Centers, Angles. 

Geometry Problem
601
Post a comment or solution
Cyclic Quadrilateral, Incenter, Excenter, Rectangle. 

Problem
563.
Regular Pentagon, Center, Rectangle, Diagonals, Angle. 

Problem
537.
Rectangle, Midpoints, Diagonal, Angle Bisector. 

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


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

Golden Rectangles Index. 

Polygon Classification. Interactive Mind Map. 