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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Marca Nuevo con Original Caja

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

NIKE Kids gratis gratis Rn (grande) 19507 Ember Ember Glow/ Metallic Silver 5c848edUpdated 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.

NIKE Kids gratis gratis Rn (grande) 19507 Ember Ember Glow/ Metallic Silver 5c848ed

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

Zapatillas de deporte con adidas Pw Tennis Hu de adidas para hombre Azul hielo / azul hielo / azul , NIKE Men s Roshe Run Vino de Oporto / Negro-Negro , Brooks Womens PureGrit 6 Negro / Ebony / Diva Pink adidas Adizero Lj Núcleo Negro, Ftwr Blanco, Naranja , adidas Adizero Hj Núcleo Negro, Naranja Solar, Ftwr Blanco , Zapatillas Drew Shoe para mujer Paige Ternero blanco Zapatillas de deporte casual Raleigh Mid W de adidas Neo para mujer Blanco / negro / blanco , Under Armour Women s HOVR Phantom NC Negro (002) / Marea Tropical Calzado de running NIKE Kids Flex 2017 RN (GS) Universidad Azul / Negro NIKE Mujeres Air Zoom Pegasus 33 Racer rosa / blanco-medianoche niebla , Zapatillas de running Questar Tnd W, para mujer, de adidas Gris crudo / blanco / azul Aero , Zapatillas Drew Shoe para mujer Paige Hueso , Under Armour Women s HOVR Phantom NC Marfil (105) / Acero , Zapatillas de running NIKE Roshe Two para mujer Blanco / Blanco-Puro Platino , Zapatillas NIKE Femenil Flex 2016 Rn Running Negro / Blanco / Gris Fresco , Zapatillas deportivas 574S Sport New Balance para hombre Beige / Beige , Zapatillas de deporte Onitsuka Tiger Mexico 66 Birch / India Ink / Latte , Calzado casual tejido NIKE NIKE para hombre Grano antracita gris 002 , Zapatillas de entrenamiento de vuelo Jordan Nike para hombre Cool Gray / Cool Gray / Wolf Gray NIKE Big Kids Air Max 90 Cuero Zapatos para correr, Ligero, Cómodo y Durable de grano completo y cuero sintético Gimnasio Red / Black-Noble Red , NIKE Women s Tanjun Iced Jade Aurora verde blanco Converse Chuck Taylor All Star Seasonal Color Hola Lavender Glow Converse Chuck Taylor All Star Seasonal Color Hola Pistola Metal / Blanco , Brooks Womens Revel Gris / Ébano / Verde azulado , Calzado de running rápido para mujer Reebok, tejido flexible Carbón / Blanco / Moonglow / Ácido rosa Sandalia deportiva NIKE Kids Kawa Slide (GS / PS) Negro Zapatillas de running NIKE Juvenate para mujer Negro / Blanco / Negro / Blanco Zapatillas deportivas 574S Sport New Balance para hombre Azul marino / Vintage Indigo Converse Chuck Taylor All Star Seasonal Color Hola Daybreak Pink ,

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 para correr Brooks Cascadia 12 para mujer Peacoat / Flor de la pasión / Bluebird Calzado deportivo New Balance para mujer Vazee Rush V3 Vivid Coral / Fiji Chaco Mujer Zcloud Sport Sandal Noche Emplumada Zapatillas Adidas Supernova Glide Boost Running Sneaker - Mujer Negro / Naranja , Zapato de running ASICS GEL-Cumulus 20 para mujer Negro / Flash Coral Zapatillas de running ASICS Gel-Nimbus 20 para mujer Azul / blanco Zapatillas de running NIKE para mujer Lunarepic Low Flyknit 2 Wolf Gray / Purple Earth , Zapatillas de running New Balance Boracay V3 para mujer Blanco negro , Zapatos OLUKAI Pehuea - Mujer Vivid Blue / Vivid Blue Bernie Mev Women s Gummies Gem Flat Negro Under Armour Women s HOVR Sonic NC Gris Nublado (101) / Blanco , Nike Men s Air Presto Essential Blanco / Blanco / Negro Sandalia de mujer Yellow Box Amor Armada Zapatos ocasionales diabéticos elásticos Lucie X Black de Dr. Comfort para mujer Negro Fibra óptica Shinmax LED zapatos, luz hasta zapatillas deportivas intermitentes para Festivales de Mujeres, Fiesta de Navidad Zapatos Led Blanco Sandalia para mujer FRYE Ally Criss Cross Slide Secoya , Salón muy fino Salsa de tango latino Zapatos de baile para Mujeres SERA1683 Tacón de 3 pulgadas + plegable Paquete de cepillo Negro , Bota de media caña Georgia GB00065 marrón Botín tobillo para mujer de Seychelles Gris pardo , Pantalón largo clásico NIKE Golf para mujer Tech Essentials Negro / gris oscuro , Zapatillas de casa de lana de invierno U-lite cálido cálido Shearling de las mujeres, zapatillas de lana caliente para las mujeres Castaño (Gamuza de piel de oveja) Bomba de cuña Blare para mujer J.Renee Sonrojo Mordenmiss Nuevo verano de primavera y verano de flores hechas a mano zapatos planos de cuero Mocasines Estilo 1 gris hueco , CLARKS Darleigh Cora Sneaker Negro , Converse Chuck Taylor All Star Core Ox Armada , TOMS Kids 10009918 Alpargata-K Marina, microfibra , Smoky Mountain Girls Lucky Girl Western Boot Snip Toe - 3614C Crema marrón Zapatillas de deporte lavables Walker Propet para mujer Hueso / Wht TOMS - Suela de lino de lino clásica, cómoda y de ajuste fácil para mujer Chambray / moldura texturizada negra , TOMS - Slip-On de lienzo clásico para hombre Black Cherry Heritage Canvas

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 NIKE Kids gratis gratis Rn (grande) 19507 Ember Ember Glow/ Metallic Silver 5c848ed 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