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 y sintético

Hecho en los EE. UU.

Caucho único

Eje mide aproximadamente parte baja del arco

TRUFUSE tecnología

ABZORB entresuela

Stabilicore

Desmontable insertar

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

Zapatillas de running New Balance 1340v3 para B01N8POW0H New mujer Balance Blanco/ morado 0e773d6Updated 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.

Zapatillas de running New Balance 1340v3 para B01N8POW0H New mujer Balance Blanco/ morado 0e773d6

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

New Balance Women s w990v4 Running Shoe Gray / Castlerock adidas Originals Alphabounce RC W para mujer Trace Blue / Super Purple / Footwear White Zapatillas de running Freedom Runner para mujer de Saucony Originals Negro ASICS Metrolyte II Shoe Women s Walking Blanco / Blanco / Blanco Zapatillas de running ASICS Gel-Nimbus 20 para mujer Negro / Blanco / Carbono , Zapatillas de running Alphabounce W para mujer adidas Performance Fresno / Neón Verde / Hielo Púrpura F16 Zapatillas de running Fresh Life Arishi V1 para mujer New Balance Plata / rosa Zapatillas de running Reebok Women s Supreme 3.0 MT Gable Gray / Fire Spark / Blanco , Zapatillas de running New Life Arishi v1 Luxe Fresh Foam de New Balance para mujer Acero Zapatillas de running New Balance para mujer 490v4 Negro / Guayaba , Zapatillas deportivas para hombre NIKE Lunar Apparent Binary Blue Metallic Silver , Calzado de running ancho NIKE para mujer Experience 7 de NIKE Negro / Blanco - Blanco , Zapatillas de running Pureboost X de adidas Performance para mujer Vista Gray S15 / Plata metalizada / Gris medio S14 En la ejecución de calzado de mujer en la nube Blanco negro , Zapatillas para correr Mizuno Women s Wave Rider 21 High Rise / Gray Stone , Zapatillas de running Under Armour Speedform Intake 2 para mujer Gris , Zapato de correr con cambio Gel-Quantum 360 Shift para mujer de ASICS Glaciar Gris / Blanco / Carbono Zapatillas de running NIKE Lunar Skyelux para mujer Antracita negra / blanca , Zapatillas de running New Balance 990v4 para mujer Lago Azul / Lago Azul New Balance Women s w940v3 Running Shoe Azul , adidas Performance Ultraboost X para mujer Trace Scarlet / Crayon White / Trace Orange Under Armour Speedform Velociti para mujeres Rhino Gray / Glacier Grey / Black Zapatillas de running Fresh Life Arishi V1 para mujer New Balance Mulberry / Black Zapatillas de running adidas Duramo 8 para mujer Gray Two / Gray Three / Energy Aqua , Zapatillas de running adidas Alphabounce Em W para mujer Tech Earth / Bliss / Crystal White Zapatillas de running adidas Originals Tubular Defiant PK Originals para mujer Rosado , Zapatillas de running NIKE Air Zoom Pegasus 34 para mujer Blanco / Plata Metálico-glaciar Azul Zapatillas de running New Balance Foam Cruz V1 para mujer New Balance Negro / sal marina Zapatillas de running de malla cruzada Nova Vam Cruz V1 para mujer New Balance Reflexión / 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 Wolky Comfort Jewel Black Snake Print Zapatillas para correr ASICS Gel-Venture 6 para mujer Phantom / Coral / Lima , KEEN Hombres Newport H2 Sandal Midnight Navy / Feather Grey Sandalia Drew Angela para mujer Dusty Multi Metallic Leather Salomon Women s X-Mission 3 W-w Menta / Deep Dahlia / Athletic Green X , Zapatillas de trail running Salomon Women s Speedcross 3 Burdeos / rosa fuerte / rosa de loto , Zapatos OLUKAI Pehuea - Mujer Pavimento / Pavimento , Zapato para caminar WW411v2 New Balance para mujer Blanco Prop & eacute; t Zapatillas para caminar TravelFit para mujer Púrpura Zapatillas de running ASICS GT-2000 6 para mujer Indigo Blue / Indigo Blue / Smoke Blue , MBT Zapatos Mujer Tunisha Mary Jane Casual cuero de zapatos / malla hebilla Negro / Nappa , Sandalia de vestir de cuero Nine West para mujer Light Gold Synthetic Zapatillas para caminar ProGrid Integrity ST2 para mujer Saucony Piedra , Sandalia Sharley Slide Vince Camuto para mujer Red Hot Rio , Skechers Women s Go 4-14918 Calzado para caminar Blanco negro , Zapatillas de tenis ASICS Gel-Solution Speed 3 para mujer Azul Indigo / Blanco / Azul Porcelana Converse Chuck Taylor All Star Seasonal Canvas High Top Sneaker Polvo morado Sandalia Taryn Rose de mujer Iris Knit Slide Negro , Sam Edelman Women s Slide Sandal de mujer Almendra / Sedona Naranja , Sandalias planas Cammie de Jessica Simpson para mujer Desnudo Blush Sandalia para mujer J.Renee Maribeth Slide Armada , Sandalia Bobbi Slide de Dolce Vita para mujer Ante azul marino , Party Party Velvet Vestido de noche bomba Colecciones, Comodidad Zapatos de boda: Salón de baile de mujeres Zapatos de baile, medio Tacón, Tango, Suave, Estándar 7015- Terciopelo negro , CLARKS Keesha Rosa Dress Pump para mujer Cuero negro Naturalizer Michelle s Dress Dress Pump Cuero negro , Zapato de construcción y construcción Nano Toe / Tater para mujer Caterpillar Fragment Negro , Trotters Lucy Ballet para mujer Armada ED Ellen DeGeneres Mujeres Antona Acero azul / acero azul niño gamuza / elástico de fieltro , Botas para mujer InterestPrint Botas con cordones con diseño exclusivo Multi 12 ara Laurel Loafer Mujer plana Taupe Snake Combo

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 Zapatillas de running New Balance 1340v3 para B01N8POW0H New mujer Balance Blanco/ morado 0e773d6 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