These are some mathematics investigations I have pursued over the years. They may be of some interest to teachers, students, or hobbyists. I try to convey a conceptual understanding, usually without rigorous proof. Some of the lessons are accompanied by questions and suggestions for extensions.

75% Gamuza / 25% Malla

Importado

Goma único

tradicional estilo retro zapatilla deportiva bases de malla y contraste ENCAP talón

espuma EVA entresuela y talón amortiguación

Some of the lessons are accompanied by questions and suggestions for extensions.

In my pursuit of a teaching career, I was told to justify the study of each concept by establishing its relevance to the students’ lives. Sorry, but I still have trouble buying into that one. Fortunately, poetry and music are rarely put to that same test. As I glance at the list below, I must concede that it would be difficult to convert any of the lessons into food, shelter, or money. These are things that interested me, and now I understand them better. If there is a reward, it is the fact that every time I do this I get better at figuring things out.

I occasionally get email from people seeking permission to use my work. Feel free to cite, quote, edit, reproduce, or distribute anything on this site. Do not worry about putting my name on it, but please do not put your own name on it.

Many of these presentations use the Geometer’s Sketchpad, but only one of them actually requires it. If you do not have the software, let me suggest that you follow this link to Key Curriculum Press and look into it.

Paul Kunkel

March 16, 2016

Updated the animations on Hanging With Galileo.

October 23, 2015

Updated the animations on Reuleaux Triangle.

October 9, 2015

Updated the animations on the Vernier Scale page of the Geometry of Surveying.

October 8, 2015

Zapatillas de deporte clásicas para Playa uso general Summer New Utility Zapatillas WL696 para mujer de New Balance Playa Arena/ Libélula 02f19e5Updated the animations on Linkages.

October 4, 2015

Updated the animations on On the Square.

September 25, 2015

Updated the animations on Tangent Circles.

September 23, 2015

Updated the lead page of Conic Sections and Construction.

The page it replaced had java animations that were not being treated well by modern browsers. New images were generated with the developmental Web Sketchpad, which is producing very satisfying results. This appears to be the future, so expect more of my pages to be similarly updated soon.

February 26, 2015

Added Book VII to the Conics of Apollonius.

This is the final surviving book of the treatise.

October 22, 2014

Added Book VI to the Conics of Apollonius.

June 10, 2014

Added Book V to the Conics of Apollonius.

Includes GSP-3 files

Includes GSP-4 files

Includes GSP-5 files
Contents:

We are given two fixed points in a vertical plane. A particle starts from rest at one of the points and travels to the other under its own weight. Find the path that the particle must follow in order to reach its destination in the briefest time.

This is a famous problem in the calculus of variations. Nothing new is presented here, but the explanation is more thorough than most.

Buffon’s Needle

An old probability exercise is aided by an interactive Sketchpad file. By manipulating the sketch, an intuitive understanding may be gained, even if the student has had no introduction to calculus.

Zapatillas de deporte clásicas para Playa uso general Summer New Utility Zapatillas WL696 para mujer de New Balance Playa Arena/ Libélula 02f19e5

Chinese Handcuffs This has no lesson, only questions. It is just an interesting animated file, which invites student investigation. It has applications for geometry,

Under Armour Women s Dash 2 Apollo Gray (101) / Blanco , Zapatillas de running NIKE Mens Lunarglide 8 Racer azul / negro , Zapatillas de running ASICS Gel-Kayano 23 para mujer Púrpura / Plata / Menta Zapatillas de running NIKE Air Zoom Vomero 12 para hombre Negro / Blanco / Antracita , Zapatillas deportivas NIKE Womens Flex Contact Wolf Gris / Blanco-Pura Platino-Cool Grey Negro / Blanco / Antracita , Zapatillas de running adidas Alphabounce Beyond para mujer Gris / gris / naranja claro , NIKE Free RN - 831509601 Fuego rosa / azul resplandor / luz violeta / rosa explosión Zapatillas de running NIKE Air Max Torch 4 para mujer Negro / Plata Metálico / Rosa Flash , Zapatillas de running ISO para mujeres de la guía Saucony Blanco azul adidas Performance Ultraboost X para mujer Trace Scarlet / Crayon White / Trace Orange , Zapatillas de running Mizuno Wave para mujer con sombra Griffin / Blanco / Eléctrico Zapatillas de running adidas Ultraboost W para mujer Táctil Azul / Táctil Azul / Negro , Zapato de running Saucony Zealot ISO 3 para mujer Gris azul Zapatillas de running ISO para mujeres de la guía Saucony Gris / menta , NIKE Men s Benassi Just Do It Athletic Sandal Oro negro / metálico Saucony Women s Cohesion 8 Running Shoe Plata / Blanco / Azul Zapatillas de running NIKE RN 2017 para mujer gratis Wolf Gray / Off White-pure Platinum-black Calzado de running NIKE Dualtone Racer para mujer Blanco / puro platino , Skechers Performance Women s Go Run 400 Obstruct Negro / púrpura Zapatillas de entrenamiento Nike Womens Metcon 3 Negro / Blanco-volt-cloro Azul , Zapatillas de running NIKE Women s Air Max 1 Ultra Essentials Cumbre Blanco / Universidad Rojo / Blanco , Brooks Women s Dyad 9 Ombre Blue / Festival Fuchsia / Mood Indigo , PUMA Men s Roma Basic Sneaker Cuero blanco / negro , Zapatillas de running NIKE Roshe One Print para tobillo y tela para mujer Negro / Brgd azul-antracita-cool gris , Zapatillas de running NIKE para mujer Lunarepic Low Flyknit 2 Azul Mediano / Negro-aluminio-electro Verde Zapatillas de running de malla cruzada Nova Vam Cruz V1 para mujer New Balance Reflexión / Blanco , Zapatillas de running New Balance 1500v3 para mujer Porcelana / Alpha Pink , PUMA Men s Roma Basic Sneaker Blanco / Peacoat / avena Zapatillas de running NIKE Air Max Flair para hombre Piedra Pómez / Legión Verde ,

trigonometry, and probability. Fair warning: The discussion revolves about
a figure that appears only when the sketch is animated. Without Geometer’s
Sketchpad, this one will make little sense at all.
Conic Sections and Construction

My emphasis is on geometric properties of the conic sections, particulary understanding that has been handed down to us in ancient texts. There also are some challenging constructions.

The Geometry of Surveying

This used to be my job, and I enjoyed studying all of the geometrical concepts that were part of the science of land surveying. In this article I discuss the instruments of the profession, their operating principles, their error, and their calibration.

Hanging with Galileo

An investigation into the catenary, the curve formed by a chain suspended at both ends. It also extends into the curve of the main cables on a suspension bridge, which, interestingly, is not a catenary.

Inversion Geometry Sandalias KEEN Venice II H2-W para mujer Negro / gris acero , Zapatilla Skechers para mujer Go Run 600-Obtain Frambuesa , Zapatillas de running adidas Alphabounce Beyond para mujer Gris / gris / naranja claro Sandalias Bali KEEN para mujer Beso de uva / Hierba Lavendar HOKA ONE ONE Zapatillas para mujer Arahi Sunny Lime / Blue Topaz , NIKE Mujeres Air Zoom Pegasus 33 Pure Platinum / blanco-negro-voltio , Chaco Mujer Zvolv Sport Sandal Hop Scotch , Zapatillas de running adidas Women s Rockadia W Trail Carbono / Acero sin procesar / Trace Scarlet Zapatillas adidas Outdoor Terrex Agravic Speed Shoe de mujer Gris crudo, Gris crudo, Gris ceniza Sockwa G4 Minimal Barefoot Shoes Gris , Taipán de mujer de David Tate Verona Champagne Lamb Calzado deportivo G-Defy Gamma-Ray para mujer Gravity Defyer Azul blanco , Zapatillas de running ASICS Gel-Cumulus 19 para mujer Negro / Plata / Tinta Peacoat Skechers Women s Walk Walk Lite-Daisy Loafer Gris pardo Cobb Hill Rockport Women s Angelina Dress Pump Burdeos New Balance 711v3 Heather Cross Trainer para mujeres Trueno / Poisonbery Diadora B. Original Sneaker para hombre Blanco / Blanco / Blanco Nike Tech Xtreme Cadet Glove Binario Azul / Azul Paramount / Lobo Gris / Blanco Entrenador campeón Gusto Cross Trainer Malla rosa clara Vans Auténtico Lavado 2 tonos marrón gris , Sam Edelman Women s Tai Sanda Coral Multi , Bota de capricho Pleaser Women s Sinister 201 B Black Pu , Bota Premium Timberland para mujer de 6 \ Simplemente Taupe Suede Coach Womens Rhoda lona alpargata Rosa brillante , Bota de moda Jessica Simpson para mujer Loring Patente de arruga negra Bed | Stu Botines para mujer estridentes Tinte Di Moro Dip Dye , Twisted X - Zapatos de conducción con cordones, entallados, para damas, moc Toe marrón , Tommy Hilfiger Women s Jouston Oxford Negro , Easy Spirit ON CUE Oxford para mujeres marrón , Mocasines de vestir de punta estrecha para mujer de Me Too Women Uva roja ,

If you have never studied inversion geometry, you can start here. The elementary concepts are explained. This page is a quick reference for the other lessons that employ inversion geometry.

Linkages

Draw a line segment. Did you use a straightedge? How do you know it was straight?

Java simulations are used to investigate a nineteenth century mechanics problem.

On the Square

The challenge: Given four arbitrary, unique points, *A*, *B*,
*C*, and *D*, construct one line through each point such that the four lines form a square.

Orthocenter What is so significant about the orthocenter of a triangle? Why does it even have a name? This investigation was prepared for a geometry teachers’ workshop. It includes a lesson handout in Word format. This lesson was written for use in a computer lab with the Geometer’s Sketchpad, but with a little editing it should work just as well with Cabri or Cinderella.

The Planimeter

A planimeter is a drafting instrument used to measure area. Its mechanism is quite simple, but understanding why it works is more elusive.

Platonic Solids

Find the inradius, circumradius, dihedral angle, surface area, and volume of all of the Platonic solids. There is also some information about some of their other interesting properties.

Reuleaux Triangle

It is not a circle, but it has constant width. Study the properties of this figure with interactive animated sketches.

Rungs and Vineyards

How is that for a descriptive title? Here are investigations of two interesting visual effects seen from a moving automobile. It includes two interactive perspective drawings, and a discussion of the cylindrical and planar projections used to create them.

The Sliding Triangle

An interesting accidental discovery – Investigate ellipses by tracing triangle transformations.

Table Patterns

Explore geometric patterns formed in a table of modular multiplication. This one requires some elementary knowledge of congruence classes and modular arithmetic.

Tangent Circles

Three circles are given. How many circles can be constructed tangent to all three? How are they constructed? This lesson includes ten animations covering all of the special cases. Some of them are very complex. A little knowledge of circle inversions would help.

Volume of a Torus Do you already know the volume of a torus? Then humor me. I just figured Zapatillas de deporte clásicas para Playa uso general Summer New Utility Zapatillas WL696 para mujer de New Balance Playa Arena/ Libélula 02f19e5 it out, and I got a chance to try out this new graphics software.

Resources

The Geometer’s Sketchpad Workshop

It is plain to see that I am very fond of Sketchpad. This page was created after the release of version 4. The idea is to have a place to exchange ideas with other users, especially those who are using the advanced features. Here are some custom tools and some information on Java Sketchpad.

Sketchpad Gallery These are some of my best sketches. You may find them useful or interesting by themselves.

Geometry Construction Reference

Thirteen elementary straightedge
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and compass constructions are described and illustrated. The original version,
in Word format, can be downloaded and distributed.

Last update: March 16, 2016 ... Paul Kunkel

For email to reach me, the word