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

Importado

Goma suela

sintético superior

Metatomical Plantilla de EVA

Non-marking suela de goma

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

Sandalias KEEN tortuga B072L6QRHL Mujer Ana Ana Cortez Flip-W Concha de tortuga c58ebd6Updated 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.

Sandalias KEEN tortuga B072L6QRHL Mujer Ana Ana Cortez Flip-W Concha de tortuga c58ebd6

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

Teva Terra Sandal para hombre Madang Blue , Sandalia Uneek O2-w de mujer KEEN Estate Blue / Harvest Gold Sandalia KEEN Women s Venice H2 Gruta Celeste / Azul Sandalias Newport H2 de KEEN para mujer Cuervo / Capri , Wolky Comfort Jewel Gray Picasso Crash Sandalia KEEN Women s Venice H2 Mineral azul / verde brillo ALMA NATURAL Sandalia de pescador Beatrice para mujer Chocolate , Sandalia ECCO Women s Offroad Lite Titanio / Concreto , Sandalia Uneek O2-w de mujer KEEN Negro Negro , Sandalias Bali KEEN para mujer Imán / gris neutro Chaco Mujer Diana Sport Sandalia Pino hueco , Sandalias Swiftwater Mesh de Crocs para mujer Gris claro , Sandalias Newport H2 de KEEN para mujer Cáñamo / azul provincial Sandalia Savannah de Ryka para mujer Azul marino / verde , Wolky Comfort Jewel Fantasía de serpiente blanca / negra posters BZees Sandalia Deportiva Jive para Mujer marrón Sandalias KEEN Mujer Whisper-w Sterling Blue / Vestido Azul Sandalia Uneek O2-w de mujer KEEN Anemone / Bright Rose , Wolky Comfort Jewel Charol negro , Sandalia para mujer NIKS Benassi Solarsoft Slide Cloro Azul / Azul Glaciar , Sandalia Yucatan ECCO Mujer Polvo / polvo OluKai Ohana Dark Java / Dark Java Sanda Verra Teva para mujer Suri Taupe Multi Sandalia deportiva Nolita para mujer Anne Klein Tela negra , Sanda Verra Teva para mujer Negro Adidas Women s Adilette CF + Logo W Sandalia deslizante Ash Blue / Aero Blue / Black , Sandalia Atlética Merrell para Mujeres, Alrededor de la Ciudad Vertical , Wolky Comfort Jewel Black Croco Sandalia de mujer Drew Alana Pewter-bronce

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 430v1 New Balance para mujer Trueno / Azalea Sandalia KEEN Women s Venice H2 Midnight Navy / Coral caliente Zapatillas de running ASICS Gel-Contend 4 para mujer Blanco / Aruba / Plata Naot Footwear Women s Brussels Hilos de plata de cuero Sandalias Newport H2 de KEEN para mujer Negro pizarra / Cantón Newton Running Womens Gravity VI Rodamina / Teal Zapatillas NIKE Flex Adapt TR Cross Trainer para mujer Gris oscuro / Blanco / Negro / Sigilo , Zapatillas de running Salomon Women s Speedcross 4 GTX W Trail Cereza de Barbados , Zapatos OLUKAI Pehuea - Mujer Vivid Blue / Vivid Blue Zapatillas de entrenamiento WX624v2 para mujer New Balance Negro Zapatillas Slip-on de mujer Skechers You Inspire Negro / gris Zapatillas para caminar Go Walk 4 Propel de Skechers Performance para mujer Blanco negro , Calzado de running Fila Memory Faction 2 de Fila Monumento / Sugarplum / Blanco Sandalias de cuero de Viv Viv de TOMS Pom natural del cáñamo , Chaco Zcloud 2 Sport Sandal para hombre Varsity Sun , Bomba de vestido Nika BeautiFeel para mujer Mezclilla Sandalia Tonya de mujer Trotters Equipaje , Sandalias de mujer Vionic Perk Carmel Backstrap Sandal Aceituna , Zapato para caminar New Balance Women s Womens 928v3 Walking Shoes Blanco Blanco , ASICS Tiger Unisex Gel-Lyte V Sanze Azul oscuro / gris piedra , CLARKS Womens Trigenic Flex Rosado La sandalia de la diapositiva de la plataforma de la correa cruzada de Unda Fix de las mujeres del arreglo Mushroom Python Print , Sandalias Jerusalén Sandalias Mujer Negro 50 sombras de blanco Colección de zapatos de baile, Noche de confort Vestido de boda bombas, Zapatos de salón Para América, Tango, Salsa, Swing, Theather Arte por 50 sombras (2.5 \ Tacones) 1154- Satén de marfil Zapatillas de ciclismo lanzadera X-Alp Pearl iZUMi para mujer Perla ahumada / Monumento Zapatos planos de tacón bajo YDN para mujer con tacón bajo, deslizamiento en zapatillas Bowknot Zapatos antideslizantes de verano en deslizamiento Desnudo , Sandalia Birkenstock de cuero Florida para mujer Habana Waxy Leather , Zapatilla de deporte Kiera Fashion Kenneth Cole New York para mujer Negro Zapatos de tierra serval Gris pardo , Soft Style de Hush Puppies Women s Jaylene Oxford Nubuck azul marino

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 Sandalias KEEN tortuga B072L6QRHL Mujer Ana Ana Cortez Flip-W Concha de tortuga c58ebd6 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