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.

Hecho por el hombre

Importado

Sintético suela

Medidas de talón aproximadamente 1.5

Parte superior de nylon

DriStepbamboo plantilla de carbón

EVA suela con goma inserciones

Malla revestimiento

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 mujer para caminar Travelite Zapatillas para mujer Travelite Propet Blanco 73bcd18Updated 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 mujer para caminar Travelite Zapatillas para mujer Travelite Propet Blanco 73bcd18

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

Zapato casual para mujer MBT Muziki Militar , Skechers Women s Go Walk Joy-15615 Sneaker Negro / rosa , Eric Michael Womens Izzy marrón , Zapatillas ONEMIX para hombre, para mujeres Zapatillas ligeras, transpirables, para caminar al aire libre Zapatillas tipo calcetines C-vino rojo / blanco Sandalias de mujer Ros Hommerson Mellow Armada Zapatillas para caminar Skechers Gostyle 15606 para mujer Rosado , Prop & eacute; t Zapatillas para mujer TravelFit Hi Walking Negro Metálico , Zapatillas para caminar ProGrid Integrity ST2 para mujer Saucony Gris oscuro Cobb Hill Rockport Mujeres Petra Mary Jane Flat Armada Earth Womens Allegro Ballet Flat Cuero suave negro Zapatos de mujer RYKA Sky Walking Cool Mist Gray / Orchid Bouquet Skechers Principio Color de malva , Walking Cradles Womens Henna Azul marino Nubuck Estampado Zapatos de mujer RYKA Sky Walking Azul marino / Lila Skechers Women s Go 4-14918 Calzado para caminar Blanco negro , Drew Shoe Women s Paradise II Velco Slip-on Negro , Skechers Women s Walk Walk Lite-Daisy Loafer Rosado , Trotters Mujer Simmy Mary Jane Flat Ante azul marino Kenneth Cole New York Mujeres Lace Up Moda Cherry Blossom Techni-Cole 37.5 Sneaker Sneaker Blanco Prop & eacute; t Zapatillas para caminar TravelFit para mujer Baya , Zapato para caminar New Balance Women s Womens 928v3 Walking Shoes Blanco azul , Jambu Women s Spain Flat rojo , Prop & eacute; t Zapatillas para mujer Wear N Wear Slip on LL Walking Sr White Zapato de caminar sin tocar Skechers Performance para mujer Go Step Ante negro , Zapatillas de mujer Reebok DMX Lite Slip Walking Plomo / Eco Azul / Cielo Azul / Blanco Skechers Women s Go Walk Joy-Paradise Sneaker Gris / azul , Skechers zapatillas de mujer You-Shine Negro / gris , Zapatillas para caminar Ryka Women s Devo Plus 2 Gris / verde azulado , Prop & eacute; t Zapatillas para mujer TravelFit Hi Walking Lt Gray

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 Zapato NIKE Roshe One femenino Total Naranja / Equipo Red-sail , Saucony Women s Ride 10 zapatillas para correr Blanco azul , Zapatillas de running NIKE Air Zoom Vomero 12 para hombre Azul profundo / Cumbre Blanco-Negro Sandalia Merrell Tetrex Crest Wrap Sport para mujer Vapor , Sandalia Yucatan ECCO Mujer Coral Blush , ALDO Mujer Zarella. Metálico Varios Zapatillas de running NIKE Zoom All Out Low para hombre Cargo Khaki / Negro , Calzado de entrenamiento cruzado TR 6 NIKE para mujeres en temporada Stealth / Hot Punch-antracita Zapatos de agua para mujer Dreamcity Zapatos deportivos atléticos para caminar Negro Blanco 789 Drew Shoe Women s Tulip Comfort Croc negro Zapatillas de running New Balance para mujer Fresh Foam Zante V3 Performance Gunmetal / Sea Salt Zapatillas para correr New Balance Rushv3 para mujer Piscis / Pigmento Drew Womens Element Nubuck marrón NIKE Men s Roshe Two Running Shoe Negro / Negro / Gris Oscuro Zapatillas de running PUMA Women s Ignite Dual WN Puma Black / Puma White Hush Puppies Power Walker Sneaker para mujer Gris pardo , Baabuk Wool Sneaker - Mujer Gris claro / negro Vivien Flat de Bella Vita para mujeres Cuero de gamuza de cabrito negro , Allrounder de Mephisto NIRO Diamonds Mary Jane Flat Grafito Gamuza / Wela Mesh , Diadora Unisex N9000 III Blanco / alto , Zapatillas de golf Adidas, sin puntas, adidas Women s W Ftwr blanco / plata mate / orquídea salvaje-tmag , Sandalia de la diapositiva Floella de la mujer de la marca de Lucky Denim ligero , Sandalia de la diadema de la guarnición de las mujeres de Vince Rosa , Tamaris Women s Fee 22425 Pump Negro Salón muy fino Salsa de tango latino Zapatos de baile para Mujer SERA7004 Talón de 2.5 pulgadas + Cepillo plegable Haz Cobre , Stuart Weitzman Women s Vigor Patente negra Mocasín de gamuza Kilty de Minnetonka para mujer marrón , Calvin Klein Womens Priscila Pizarra niño gamuza / neopreno , Zapatillas de señora Jacques Levine 9854 Shearling Gris , TOMS - Suela de lino de lino clásica, cómoda y de ajuste fácil para mujer Black Heritage Canva

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 mujer para caminar Travelite Zapatillas para mujer Travelite Propet Blanco 73bcd18 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