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.

Malla sintética

Importada

Flexion Ajuste

PGuard

Rearfoot y antepié GEL

Personal Heel Fit

Solyte; Sistema Trusstic; AHAR

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 para tenis ASICS Gel-Challenger 11 Negro para mujer ASICS Negro/ Negro/ Rosa Caliente 8700e4dUpdated 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 para tenis ASICS Gel-Challenger 11 Negro para mujer ASICS Negro/ Negro/ Rosa Caliente 8700e4d

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

PUMA Clyde Core Sneakers para mujer Blanco Z-CoiL Calzado de alivio de dolor Calzado de tenis de cuero fuxia resistente a las resbalones para mujeres Fucsia , Zapatillas de tenis 696v3 New Balance para mujer Pigmento / coral vivo adidas Originals Hombres Superstar 80s PK Gris , Zapatillas de tenis Hard Court WC696V3 de New Balance para mujeres Plata blanca Zapatillas de tenis ASICS Gel-Solution Speed 3 para mujer Glacier Sea / Indigo Blue / Arctic Aqua Lakai Limited Calzado para hombre Daly Ante blanco , Zapatilla para mujer Dr. Comfort Katy Púrpura , Zapatillas de tenis adidas Stella McCartney Barricade Boost para mujer Mid Grey and Core R Rojo de núcleo gris medio Drew Shoes Toscana Diabético Terapéutico Mujer Profundidad Extra Zapatos de Cuero / Malla Con Cordones Negro / Combo Zapatilla deportiva con cordones Slip-On Onitsuka Tiger Mexico 66 Blanco-turquesa , Zapatillas bajas con cordones All Star Canvas de Converse Chuck Taylor Carbón , Zapatillas de tenis Wilson Rush Pro 2.5 para mujer Azul Curacao / Blanco / Coral Fiery , Zapato Dantera, para hombre, L Low Waxed Court Blanco / Vestido Blues / Fiery Red , Zapatillas de tenis ligeras 996v2 New Balance para mujer Verde azulado / azul marino Converse Chuck Taylor All Star Core Ox Blanco negro Zapatilla de running Titan II para hombre Diadora Blue Bell / Gray Ash Dust Zapatilla de running Titan II para hombre Diadora Noches azules / Paloma / Noches azules Zapatillas para mujer Del Rey TOMS Gris oscuro Zapatilla deportiva con cordones Slip-On Onitsuka Tiger Mexico 66 Blanco apagado / blanco , APL: Athletic Propulsion Labs Zapatillas de running mujer Techloom Phantom Melocotón medianoche / tropical Merrell Womens Chameleon 7 Mid Waterproof Hielo ASICS Tiger Unisex Vickka TRS Aloe / pelusa Zapatillas para mujer Del Rey TOMS Sub azul Diadora N9000 Men Toe Snthetic Blue Sneakers Rosa rosa sombra / magenta nativo AP Mercury Liteknit Clay Pink / Shell White / Natural Rubber , New Balance Wrl247hk para mujeres Chocolate Zapatillas de tenis rígidas 996v3 de New Balance para mujeres Pigmento Zapatilla para mujer Dr. Comfort Katy Verde y Turquesa ,

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 Skechers Women s Go Run Forza 3 Rosado , Sandalia deportiva Tirra para mujer Teva Teal / Dark Shadow Chaco Mujer Diana Sport Sandalia Biselado negro , Zapatillas para correr de carretera Altra One V3 para mujer Negro Salomon Women s Speedcross 4 W Trail Runner Surf hawaiano Chaco Women s Z2 Classic Athletic Sandal Brocade Pine , ALMA NATURAL Ballet femenino femenino Azul marino liso Sandalia metálica Showrunner de nueve mujeres del oeste Oro claro / Metálico , Zapatillas de running NIKE para mujer Lunarepic Flyknit Shield Negro / Metálico Plata-oscuro Gris-sigiloso Ros Hommerson Chelsea Mary Jane Slip On Shoes para mujer Estaño , Sandalia de tira de Ghillie Bre-Italy Bella Vita para mujer Cuero de ante taupe Sandalia Drew Cascade para mujer Denim Blue Nubuck , Sam Edelman Gemma Oro fundido Chaco Mujer Zcloud 2 Sport Sandalia Testla Melocotón , Skechers Women s Define Sneaker Negro Calzado de entrenamiento casual Comfort WX623v3 New Balance para mujer Plata blanca MONTAÑA BLANCA Mujer Marvy Peep-Toe Mule Aceituna , Drew Smiles Slip para mujer Azul / Microdot , Furgonetas CLASSIC SLIP EN ZAPATOS DE PATINAJE Negro (lienzo) , Converse Chuck Taylor All Star Seasonal Canvas High Top Sneaker Azul marino / blanco , Sandalia con tiras metálicas Violet Shimmer de Taryn Rose para mujer Poppy Silky Suede Sandalia para mujer Kate Spade New York Coby para mujer Negro Zapato de personaje de luz de posición de estudiante 650 de Capezio Negro Zapatos OLUKAI Pehuea - Mujer Pokeberry / Pokeberry Zapatillas Adidas Unisex Performance Adizero Lj Track Blanco / Solar Rojo / Plata Metálica , Zapato clásico Haflinger para mujer Negro Zapatillas de casa Mulise Unisex - Zapatillas de interior y exterior de lana - Made in Europe Fuchsia Multi , LifeStride Women s See This Dress Pump Negro Indigo Rd. Gris pardo , Propet Walkers Evolution Oxford lavable de las mujeres Gris / rosa

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 para tenis ASICS Gel-Challenger 11 Negro para mujer ASICS Negro/ Negro/ Rosa Caliente 8700e4d 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
3151810

3160115

6561702

7360430

9889066

9893632

12188018

12852391

18222579

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