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.

Textil, etileno Acetato de vinilo, Caucho

Importado

Caucho único

Threadborne superior para una transpirable, similar a la compresión ajuste que entrega ligero direccional fuerza

bordado construcción agrega estructura y bloqueo soporte del mediopié

Ligero, malla transpirable aumenta la ventilación y comodidad

Interna botín de tobillo proporciona un ajuste, de apoyo ajuste

moldeado Amortiguación cargada forma de plantilla al pie para un personalizado ajuste y sin igual comodidad

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

Under Armour Threadborne Fortis/ para Under mujer Threadborne Negro (001)/ Stealth Gray b2b1aaeUpdated 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.

Under Armour Threadborne Fortis/ para Under mujer Threadborne Negro (001)/ Stealth Gray b2b1aae

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

361 Zapatillas de running para mujer 361-Enjector Negro / Blanco / 0900 , Zapatillas de running adidas Ultra Boost para mujer Azul Calzado deportivo New Balance Vazee Urge v1 para mujer Púrpura / amarillo , Zapato de running ASICS GEL-Cumulus 20 para mujer Azure / Blue Print Zapatillas de entrenamiento Nike Womens Metcon 3 Cool Grey / Solar Red-black-pure Platinum Zapatillas de running NIKE Air Huarache para hombre Blanco / Blanco-blanco-negro New Balance Women s w940v3 Running Shoe Plata , Zapatillas de running NIKE Women s Air Max 1 Ultra Essentials Azul , nike womens air max 1 JCRD zapatillas para correr 819808 zapatillas zapatos Hematita Metálica / Negro-gris oscuro Zapatillas de running ASICS Gel-Cumulus 19 para mujer Negro , Zapatillas de running Fresh Life Arishi V1 para mujer New Balance Negro , Zapatillas de running adidas Women s Edge Lux W Gris / gris / blanco cristal , Zapatillas para correr Mizuno Women s Wave Enigma 6 Púrpura / blanco , Zapatillas de running acolchadas 420v4 para mujer New Balance Gris , Zapatillas para correr Nike Women s Free Rn Flyknit 2017 Tierra púrpura / negro , Zapatillas de running adidas Alphabounce Beyond para mujer Blanco / Gris / Gris Zapatillas de running NIKE Air Zoom Vomero 12 para hombre Azul , Saucony Women s Cohesion 8 Running Shoe , Zapato para correr ASICS Conviction X 2 para mujer Negro / Carbón / Flash Coral , Zapatillas de running adidas Cloudfoam Xpression W para mujer Blanco / Blanco / Haze Coral , Zapatillas para correr Brooks Cascadia 12 para mujer Peacoat / Flor de la pasión / Bluebird , Zapatillas de running NIKE para mujer Lunarepic Low Flyknit 2 Negro / Gris oscuro / Azul Racer / Negro Zapatillas de running New Balance para mujer 940v3 Azul negro , Zapatillas de running NIKE Air Huarache Run para mujer Dark Stucco / Pale Gray Brooks Women s Adrenaline GTS 17 Plata / púrpura Cactus flor / Bluebird , Zapatillas para correr New Balance W840V3 para mujer Gotita Zapatillas de running ASICS Gel-Cumulus 19 para mujer Aruba azul / azul de Aruba / azulejo turco Nike Hombres Air Zoom Pegasus 33 Gris oscuro / negro - blanco NIKE W Air Huarache City Low Women Ah6804-100 Blanco / Blanco-blanco ,

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 Air Max Thea Ultra FK para mujer Universidad Rojo / Negro-blanco , Tacones Pleaser para mujer Infinity 902 Negro Negro Sandalia Savannah de Ryka para mujer Coral / gris Zapatillas de running New Balance Coas V3 para mujer Silver Mink , Zapatillas de deporte con adidas Pw Tennis Hu de adidas para hombre Verde claro, blanco , Converse Chuck Taylor All Star Seasonal Color Hola Blanco negro , Nike Men s Air Presto Essential Juego Royal / Black-black , New Balance WT510RS3 Trail Running Shoes para mujer Negro Zapatillas de running EM Road M2 v2 para mujer Pearl Izumi Paloma / Rosa Violeta Zapatillas para correr Nike Women s Free Rn Flyknit 2017 Multicolor / Multicolor Drew Smiles Slip para mujer , Bomba de espejos Zahn de Naturalizer para mujeres Negro , Zapatilla deportiva Skechers You-14958 para mujer Negro , Chancletas bíblicos unisex de cuero genuino (Jesús - Yashua) Belén negro estilo Zapatillas para caminar Nell Ryka para mujer Azul marino / rosa Mocasín de mujer RIALTO Vette Azul Reebok Crossfit Nano 7.0 Track Shoe para mujer Vitamina C / Solar Amarillo / Negro / Plomo , Converse Unisex Chuck Taylor All-Star Top casual Sneakers en Classic Estilo y color y lienzo duradero Uppers Blanco negro Vince Camuto Sandalias Ellanna Slide para mujer Cozumel KENDALL + KYLIE Sandalia de mujer Sammy Slide Negro Zapatos de césped del escuadrón femenino Boombah - 14 opciones de color - Varios tamaños Azul marino / rojo Sam Edelman Women s Slide Sandalia Cuero de gamuza amarillo Zapatillas Jig Foo Mujer Zapatos de baile Kmeioo Slip On Mocasines, mujeres Bordado mula Zapatos con felpa Terciopelo de piel de cordero Sin respaldo Toe Mule Slides Tacón rojo vino tacón Bota de invierno UGG Classic Mini II para mujer Coral vibrante Trotters para mujer Dea Slingback Pump Armada , Pantuflas Wilma de Katy Perry para mujer Carbón Frye mujeres Phillip Chukka Cuero negro suave de la vendimia Zapatillas de deporte lavables Walker Propet para mujer Sr Bone / White CLARKS Mujer Jocolin Gia Oxford Microfibra perforada gris oscuro

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 Under Armour Threadborne Fortis/ para Under mujer Threadborne Negro (001)/ Stealth Gray b2b1aae 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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11859297

12244831

12787360

14001326

14130730

17052570

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