# Classroom Resources Index – Geometry

## Classroom-Ready Resources and Teaching Suggestions

Browse index of informative background articles for geometry.

Aiding the Teaching of Geometry and Affording Mathematical Recreation: Paper Folding in the Spirit of Sundara Rao of Madras by Peggy Aldrich Kidwell
A history of paper folding in mathematics education that focuses on the background, publication, and reception of Sundara Rao’s 1893 Geometrical Exercises in Paper Folding. The article also describes several potential classroom activities for secondary and undergraduate students of geometry and preservice teachers.

An Investigation of Historical Geometric Constructions, by Suzanne Harper and Shannon Driskell
Dynamic geometry software is used to demonstrate early Greek attempts at the trisection of an angle and the squaring of a circle.

Dear Professor Greitzer, by Joe Richards and Don Crossfield
A letter to Sam Greitzer, late editor of Arbelos, outlining a plan for developing the derivation of two formulas for calculating $\pi$ in a geometry course.

Episodes in the History of Geometry through Models in Dynamic Geometry, by Eduardo Veloso and Rita Bastos
Classroom lessons based on four episodes in the history of geometry where dynamic geometry (e.g., The Geometer’s Sketchpad) helps in understanding the ideas.

Kepler and the Rhombic Dodecahedron, by Roberto Cardil
Resources for sharing Kepler’s fascinating studies of the rhombic dodecahedron with students.

Need the Area of a Triangle? The Pope Can Help! by Betty Mayfield
Gerbert d’Aurillac on finding the area of an equilateral triangle, with exploration activities for students.

Oliver Byrne: The Matisse of Mathematics, by Susan M. Hawes and Sid Kolpas
The most complete biography of Byrne to date, along with tips for teaching with his famous Euclid in Colours.

Proportionality in Similar Triangles: A Cross-Cultural Comparison, by Jerry Lodder
A student module based on a comparison of the Greek and Chinese approaches to the idea of similarity.

Van Schooten’s Ruler Constructions, by C. Edward Sandifer
With suggested exercises for use in a geometry course in the “Notes to teachers” section.

## Informative Background Articles

Browse index of classroom-ready resources and teaching suggestions for geometry.

Approximate Construction of Regular Polygons: Two Renaissance Artists, by Raul A. Simon
Explanation of approximate constructions of regular pentagons for the use of artists offered by Leonardo da Vinci and Albrecht Durer.

E. G. Ziegenbalg’s Danish Translation of Euclid’s Elements, by Toke Knudsen
Introduces the first (1744) translation into Danish of the classic geometry text, influences on its content that led to a distinctive pedagogical approach, and the notable family who owned the author’s copy.

Mabel Sykes: A Life Untold and an Architectural Geometry Book Rediscovered, by Maureen T. Carroll and Elyn Rykken
Biography of a little-known high-school mathematics teacher and discussion of her publications, particularly the lavishly-illustrated 1912 A Source Book of Problems for Geometry Based upon Industrial Design and Architectural Ornament.

Pythagorean Cuts, by Martin Bonsangue and Harris Shultz
Discussion of how Euclid's proof of the Pythagorean Theorem can be adapted to shapes other than squares.

Some Original Sources for Modern Tales of Thales, by Michael Molinsky
Earliest known sources for stories about Thales and applets illustrating measurements methods attributed to him.

Trisecting an Angle Using Mechanical Means, by Keith Dreiling
Four methods in all by Hippias, Archimedes, and Nicomedes, illustrated with interactive applets.