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.

Cuero y sintético

Importado

Caucho único

\\ u2022 Sintético y textil superior

\\ u2022 Merrell Air Cushion en el talón absorbe choque y agrega estabilidad

\\ u2022 M Seleccione la suela GRIP sintoniza cada suela con tracción duradera que se agarra cuando y donde necesitas eso

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

Sandalia Terrell Olive Ari Convert mujer Sport de Merrell para mujer B078GB9TK9 Dusty Olive 5d3feabUpdated 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.

Sandalia Terrell Olive Ari Convert mujer Sport de Merrell para mujer B078GB9TK9 Dusty Olive 5d3feab

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

Adidas Women s Adilette CF + Logo W Sandalia deslizante Negro / Negro / Negro Sandalias KEEN Womenport Newport Hydro-W Imán / Navega por la Web Sandalia de mujer KEEN Rose Imán / Gárgola , Sandalia original Teva Women s Original Monterey-tan , CLARKS Womens Wave Grip Negro sintético OluKai Kulapa Kai Dragon Fruit / Black Sandalias Bali KEEN para mujer Beso de uva / Hierba Lavendar , Mordenmiss - Sandalias Huarache de cuero, para mujer, de verano, zapatos planos de tacón Estilo 2-negro , Sandalia Yucatan ECCO Mujer Atmósfera / Hielo Blanco / Negro NIKE Women s WMNS Benassi Duo Ultra Slide, negro / negro Negro Negro , Skechers Performance On The Go 400 Tropical Flip Flop Grey Tropical , Chaco Zcloud 2 Sport Sandal para hombre Pirámide Verde BZees por Naturalizer Dream Negro , Merrell Women s Around Town Print Sandalia atlética Fiery Red Wolky Comfort Jewel Fantasía de serpiente blanca / negra posters , Sandalia Tanga Loea de mujer OLUKAI Negro Negro , Sandalia Teva Women s W Hurricane Xlt2 Sport Negro , Sandalias KEEN Venice II H2-W para mujer Negro / gris acero , Sandalias Efecta de mujer Easy Spirit Azul medio Sandalia para mujer Teva Terra-Float Travel Knit Legion Blue , Sandalia para mujer Merrell, alrededor de la ciudad Rosa Sandalias Newport H2 de KEEN para mujer Cáñamo / Gorra blanca , Chaco Women s Z2 Classic Athletic Sandal Edredón dorado ALMA NATURAL Sandalia de pescador Beatrice para mujer Lagarto negro , Sandalia deportiva Tirra para mujer Teva Atlántico Norte Flip-flop Teva Women s Mush II Companera Black Sandalia original premier universal Teva W de mujer Beach Break Deep Wisteria , Drew Womens Cascade Denim Blue Nubuck Corkys Rock Mujer Slip On Azul Multi ,

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 Reebok Zprint Her MTM Wvn para mujer Blanco negro Zapatillas de running ASICS Gel-Cumulus 19 para mujer Gris medio / Carbono / Amarillo de seguridad Zapatillas Reebok Mujer Print Her 2.0 Camo Track Camo - Negro / Blanco Zapato de running ASICS GEL-Kayano 22 para mujer Gris plata / Pistacho / Coral Fiery , Sandalia deportiva Coleman 2.Zerogrand Slide de Cole Haan, cuero negro Cuero negro Sandalia Drew Element para mujer Denim Blue Nubuck NIKE W Air Huarache City Low Women Ah6804-100 Blanco / Blanco-blanco Zapatillas de mujer Reebok DMX Lite Slip Walking Blanco negro , Sandalias de cuero de Viv Viv de TOMS Cáñamo natural / pompones , Bella Vita Mae-Italia Mujeres WW Sandalia de tobillo marrón claro con tacón abierto Cuero marrón Vionic Rest Farra - Sandalias de apoyo para mujeres Corcho de oro , Zapatillas ONEMIX para hombre, para mujeres Zapatillas ligeras, transpirables, para caminar al aire libre Zapatillas tipo calcetines C-vino rojo / blanco Zapato de entrenamiento cruzado TR-4 Trainer Gel-Craze TRY de ASICS para mujer Azul índigo / Azul índigo / Rosa fuerte , Salvatore Ferragamo Mujer Varina Nueva Bisque , Drew Shoe Women s Tulip Comfort Brown Croc Gola Womens Harrier 50 Suede Báltico / Blanco Converse Chuck Taylor All Star Core Ox rojo Zapatilla de deporte KAANAS Santa Fe Fashion Skate Slip-on Casual Sneaker Arena Converse Chuck Taylor All Star Seasonal Canvas High Top Sneaker rojo , BareTraps Women s Fergy Slide Sandal Natural Sam Edelman Women s Bay Slide Sandal Cuero negro Vince Camuto Sandalias Ellanna Slide para mujer Urban Lux Así que Danca CH99 3 Heel con T-Strap Character Shoe Caramelo Zapato de Split Flex para mujeres de Bloch Dance Broncearse ED Ellen DeGeneres Mujeres Lilliane2 Negro / Oro Animal Avalon Nappa / Eco Sheep , CLARKS Mujer Caddell Hop Boot Armada Bota de cuero Timberland para mujer Keele Ridge WP Leather Mid Winter Marron oscuro , Corral Women s Patch Western Snip Toe Boots Marrón, coñac , Zapatillas Slip-On Roamer SAS para Mujer Armada , TOMS - Suela de lino de lino clásica, cómoda y de ajuste fácil para mujer Ballenas bordadas

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 Sandalia Terrell Olive Ari Convert mujer Sport de Merrell para mujer B078GB9TK9 Dusty Olive 5d3feab 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