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.

Sintético

Importado

Caucho único

Eje mide aproximadamente parte baja del arco

Rearfoot GEL acolchado Sistema: Atenúa choque durante el impacto fase y permite para una transición sin problemas a medio cuerpo.

Desmontable Plantilla: una plantilla que puede ser eliminado para acomodar una ortesis médica.

Extraíble Plantilla: una plantilla que puede ser eliminado para acomodar una ortesis médica.

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 para B01H2MCR90 correr ASICS Gel-Venture 6 19955 para mujer Phantom Phantom/ Coral/ Lima 22e0e8bUpdated 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 para B01H2MCR90 correr ASICS Gel-Venture 6 19955 para mujer Phantom Phantom/ Coral/ Lima 22e0e8b

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

Adicción a las mujeres de Brooks 13 Ébano / Plata / Pagoda Azul Zapatillas de running Saucony Women s Cohesion TR11 Gris / morado , Zapatillas de running NIKE Airstream Sequent 3 para mujer Negro / Blanco-gris oscuro , Nike Men s Air Presto Essential Negro Zapatillas para correr Saucony Women s Excursion Tr11 Gris rosado , Zapato de running ASICS para mujer Torrance Negro / Gris piedra Saucony Kineta Relay Runshield Running Shoe para mujer Negro / Menta , NIKE Women s Revolution 4 Running Shoe Blue Pure Platinum Purple Zapatillas para correr New Balance W840V3 para mujer Trueno Brooks Womens Hyperion Peacoat / Purple Wine / Aruba Blue Saucony Women s Guide 10 Zapatillas para correr Plata / Berry New Balance Women s w990v4 Running Shoe Gray / Castlerock Amortiguación 635v2 New Balance para mujer Plata Zapato deportivo ASICS Gel-Cumulus 18 para mujer Acuario / Flash Coral / Blue Jewel , Zapatillas de running NIKE Air Max Torch 4 para mujer Blanco , Zapatillas para correr Saucony Women s Excursion Tr11 Gris rosado , Zapatillas de running adidas Ultraboost W para mujer Pizarra negra / negra / oscura Zapato de running ASICS GT-2000 4 para mujer Carbón de leña / Flash Coral / Flash Yellow , Zapato de running Saucony Zealot ISO 2 para mujer Azul marino / azul / sil , Zapatillas de running Saucony Women s Cohesion TR11 Gris / morado Zapatilla de running Pearl Road N2 v2 para mujer Pearl iZUMi Deep Lake / Lime Punch Calzado de running New Balance para mujer 530v2 de New Balance Reflejo / Luz Porcelana Azul , Zapatillas de running Mizuno Wave Rider 20 para mujer Negro / Blanco / Rosa Glo Zapatillas deportivas NIKE Womens Flex Contact Wolf Gris / Blanco-Pura Platino-Cool Grey Wolf Gray / Metallic Rose Gold , Zapatillas de running NIKE Free Run para mujer - SU16-10 - Blanco Mango / Sunset Glow , Zapatillas de running Reebok Women s Run Supreme 2.0 Mystic Maroon / Poison Pink / White Zapato de running Fuzex Rush para mujer de ASICS Medio gris / Bay / Flash Coral NIKE Men s Flex 2017 RN Negro / Hematita Metálica / Antracita / Gris Oscuro , Calzado deportivo de running New Balance Foam Cruz V1 de New Balance para mujer Silver Mink / Outerspace ,

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 Zapatillas de running Nike Kids Air Max Zero Essential GS Blanco / lobo blanco gris NIKE Mujeres Air Zoom Pegasus 33 Púrpura , Zapatillas para correr Nike Women s Free Rn Distance 2 Blue Lagoon / Black-industrial Blue Zapato de agua Tetrex Rapid Crest para mujer Merrell Negro , Sandalia Miel Mooz para mujer Pantalones Zapatillas de running New Balance 520v3 para mujer Gris Zapatillas deportivas sintéticas Drew Shoe para mujer Flamenco Imprimir Sanda Verra Teva para mujer Surf Negro / Multi , Zapatilla Ascot de hombre UGG Teal / Sahara Zapatillas ONEMIX para hombre, para mujeres Zapatillas ligeras, transpirables, para caminar al aire libre Zapatillas tipo calcetines Blanco negro Sandalia Bella Vita IMO-Italia para mujer Cuero de whisky Supra Vaider LC Sneaker Carbón blanco , Zapato para caminar Skechers Women s You Negro , Supra Vaider Skate Shoe Blanco negro , Converse Unisex Chuck Taylor All-Star Top casual Sneakers en Classic Estilo y color y lienzo duradero Uppers Midnight Indigo Converse Chuck Taylor All Star Seasonal Canvas High Top Sneaker Rosado , Circus by Sam Edelman Sandalia Ola Slide para mujer Caparazón rosa Sandalia de la diapositiva de Florene de las mujeres de Lucky Brand Misty Rose Sandalias planas para piscina Walking Cradles para mujer Abrigo de cuero / corcho estampado serpiente natural Gorro adulto Gore Insert Jazz, T7602 Broncearse Así que Danca CH50 Character Shoe con 1.5 Heel Negro Mocasines casuales Alpargata Deconstructed de TOMS para mujer Oxford Tan Suede Trotters Lucy Ballet para mujer Estaño , Bomba Francesca de mujer Adrianna Papell Mosaico de oro Lame , Very Fine Dance Shoes 2707 (Grado de competición) 2.5 \ Brownsatin TOMS Clásicos de mujer Rojo clásico Bota Kikka para mujer Dromedaris Teal , QZUnique Mujeres Botines planos con borlas de cuero genuino con cremallera Martin Boots Negro SPYLOVEBUY KIND Botines de tacón alto con tacón alto y punta en punta con cremallera para mujer Estilo de gamuza negra , Camisa de mujer Ariat Show de Aptos Blanco

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 para B01H2MCR90 correr ASICS Gel-Venture 6 19955 para mujer Phantom Phantom/ Coral/ Lima 22e0e8b 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