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.

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Importada

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Slide sandalia con tejido T-correa superior que ofrece adornos sólidos y gancho ajustable Correa

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 Reggae Skechers Mujer Reggae T correa B008ORASVC Taupe T Ethnic Print 0af2c99Updated 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 Reggae Skechers Mujer Reggae T correa B008ORASVC Taupe T Ethnic Print 0af2c99

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

Sandalias para mujer TOMS Lexie Open Toe Casual Slingback Rose Gold Specchio / Hemp Sandalia Patrese de estilo suave para mujer Patente blanca Apéndice Gris pardo , Sandalia Harley-Davidson Ames Slide para mujer Negro Chaco Mujer Zcloud 2 Sport Sandalia Testla Melocotón , Sandalia FitFlop Shimmy Suede Slide para mujer Pale Gold , CLARKS Sandalia Sarla de Gladiador de Coro para Mujer Cuero negro , Sandalias de tacón de soñador Easy Street para mujer Broncearse Sandalias de diapositivas casuales Easy Street Womens Conca Fabric Open Toe Natural , Birkenstock Milano Sandalia de Cuero Unisex Negro Vionic Rest Farra - Sandalias de apoyo para mujeres Patente roja , Sam Edelman Women s Slide Sandalia Plata , Sandalias de cuero de Viv Viv de TOMS Chambray negro texturizado Sandalia Tali Mini Bow de Cole Haan para mujer Patente negra , Sandalia de cuña de la alpargata de la fiesta de baile de las mujeres chinas Camel Suede OOFOS Unisex Ooriginal Sport Thong Flip Flop Rojo blanco azul , Alpargata Chambray Clara denim de mujer TOMS Drizzle Grey Hemp / Multi Tribal , Sandalia de cuña Karmen de mujer Alegria Dazzler de oro , Sandalias de cordones Joanie Tobillera para mujer de SOREL Paloma , Vestido de dama de honor único de Abby L019 para mujer vestido de fiesta de la boda vestido de cono Sandalias de microfibra Astilla-c (talón cónico) , Easy Street 30-8320 Sandalia airosa para mujer Armada , Sandalia de gladiador sintético Xema de Nine West para mujer Light Natural Multi , BareTraps Women s Dusk Sandal Caramelo Sandalia Savannah de Ryka para mujer Moonrock / Snowline Ecru KEEN Women s Uneek 8MM Sandal Tinta Azul / Capri Sandalia de vestir Desi Easy Street para mujer Negro Patente / Negro , LifeStride Womens Corinne Blanco , Good-memories 2018 verano mujer zapatillas plano antideslizante interior informal peludo playa sandalias Franja verde roja , Sandalia Drew Cascade para mujer Nubuck azul marino

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 Naot Footwear Women s Brussels Cuero de mar polar Chaco Women s ZX2 Classic Athletic Sandal Motif Eclipse , Sandalia deportiva NIKE Kids Kawa Slide (GS / PS) Total Naranja / Foto Azul / Gamma Azul / Blanco , Sandalias de tirantes Sunstone para mujer Merrell Sodalita , PUMA Men s Roma Basic Sneaker Negro / Rio Rojo , Nike Men s Air Presto Essential Dusty Gray / University Red / Hyper Cobalt Zapatillas deportivas 574S Sport New Balance para hombre Coco tostado / blanco Zapatillas de running NIKE Air Max 2017 para mujer Té Berry Puerto Vino Lobo Gris 601 Zapato de running Fuzex Rush para mujer de ASICS Rosa fuerte / negro / blanco Timberland Flyroam Go Lace Chukka para mujer Negro azabache Zapatillas para correr Salomon S / Lab Speed 2 para hombre Negro / Racing Rojo / Blanco , Zapatillas de running Gobiv2 para mujer New Balance Poisonberry / Black , Skechers Women s Walk Walk Lite-Daisy Loafer Armada , FRYE Blair Harness Sandal para mujer Gris Zapatillas para caminar Omni Walker Grid de mujer Saucony Negro Zapatilla Ascot de hombre UGG Pewter / Sahara Cobb Hill Rockport Women s Angelina Dress Pump Negro , K-Swiss Women s Bigshot Light 3 Blanco / Acuario / Plata Zapatillas bajas con cordones All Star Canvas de Converse Chuck Taylor rojo Sandalia New Balance para mujer City Slide Negro Sandalia Slide de Elina de Franco Sarto para mujeres naranja , Calzado de ballet Freeform FF01 Femenino de Capezio Caramelo , Capezio DS11 Fierce Dansneaker para mujer Negro , Mocasín Sabrina Moc II Lamo para mujer Franja beige Zapatos de ciclismo Vittoria Ikon Blanco , Estimado Zapatillas de piel de oveja de Marruecos Babouche ZELLIGE Índigo ALT expansor de arranque de bobina Negro Bota de mujer Kamik Rogue 9 Negro , Zapatos planos de tacón bajo YDN para mujer con tacón bajo, deslizamiento en zapatillas Bowknot Zapatos antideslizantes de verano en deslizamiento Negro , ED Ellen DeGeneres Womens Ellert Gamuza de ternera engrasada de laguna ,

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 Reggae Skechers Mujer Reggae T correa B008ORASVC Taupe T Ethnic Print 0af2c99 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

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