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 y malla

Hecho en los Estados Unidos y Importado

Caucho suela

Plataforma mide aproximadamente 0.75 pulgadas

10mm caída del talón-dedo del pie

Doble densidad espuma de cuello

Reflectante detallando

Blown antepié 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

Zapatillas de Negro running New Balance New 990V3 990V3 para mujer Negro ac56879Updated 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 Negro running New Balance New 990V3 990V3 para mujer Negro ac56879

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 w940v3 Running Shoe Plata , NIKE WMNS Zoom Fly Women 897821-411 Blanco negro Zapatillas de running adidas Pureboost Xpose Clima para mujer Energy Blue / Energy Blue / Collegiate Navy Zapatillas de deporte Reebok Print Run Dist para hombre Negro / Aleación Zapatillas para correr Nike Women s Free Rn Flyknit 2017 Negro / antracita , Zapatillas de running New Life Arishi v1 Luxe Fresh Foam de New Balance para mujer Acero , Zapatillas de running Brooks Womens Ghost 10 Neutral acolchadas Blanco / morado / rosa Zapatillas de running PUMA Women s Speed 500 Ignite Tobillo-Alta rojo , Calzado deportivo de running New Balance Foam Cruz V1 de New Balance para mujer Melocotón espolvoreado , Zapatillas de running NIKE Women s Air Max 1 Ultra Essentials Azul ASICS Metrolyte II Shoe Women s Walking Hielo medio gris / gris medio / albaricoque , Nike Hombres Air Zoom Pegasus 33 Azul Zapatillas de running New Balance 790v6 para mujer Espacio exterior / guayaba Zapatillas de running Nike Kids Air Max Zero Essential GS Heather gris , Zapatillas de running New Balance Zante v4 Fresh Foam para mujer Rosado , Zapato de running ASICS GT-1000 6 para mujer Negro / Blanco / Atlantis , MBT Shoes Mujeres GT 17 Athletic Shoe Cuero / Malla Con cordones Blanco negro Zapatillas de running adidas Alphabounce Beyond W, para mujer Ecru Tint / Ash Pearl / Ash Pearl , Zapatillas de running Adidas Women s Energy Cloud WTC W Heather / White / Tech Grey Zapatillas de running NIKE Lunartempo 2 para mujer Hyper Violet / Black / Concord / Gamma Blue , Zapatillas de running Brooks Womens Glycerin 15 Neutral Max Cushion Plata / gris / rosa Zapatillas de running NIKE Air Huarache para hombre Industrailblue / Midnightnavy , Zapato de running ASICS Gel-Quantum 360 cm para mujer Punto medio gris / glaciar / coral Zapato deportivo para acolchado 635v2 New Balance para mujer Plata / Amarillo Zapatillas de running NIKE Air Zoom Pegasus 34 para mujer Negro / Blanco / Gris Oscuro / Antracita Zapatillas de running NIKE Zooms Winflo 4 para mujer Gris / rosa-m Zapatillas de running Under Armour Speedform Intake 2 para mujer Puerto marítimo (300) / Marfil , Zapatillas de running Under Armour Speedform Slingshot para mujer - SS16 Pedernal , Zapatillas de running New Balance 1340v3 para mujer Gris oscuro ,

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 Zapato deportivo para acolchado 635v2 New Balance para mujer Pigmento Zapatillas de running NIKE Lunar Skyelux para mujer Dark Purple Dust / White / Loyal Blue Zapatillas de running New Balance NYC Fresh Foam Zante V3 para mujer Negro Zapatillas de running adidas Alphabounce 2 M Maroon / Maroon / Mystery Ruby , Sandalia KEEN Clearwater CNX para mujer Ultra violeta / blanco susurrante , Zapatillas de running NIKE Women s Air Max 1 Ultra Essentials Cumbre Blanco / Sin prisa Rojo / Blanco Zapatillas de running NIKE Air Max Torch 4 para mujer Cool Grey / Hyper Violet / Hyper Punch , MT-onemix Women Men Awesome 3-en-1 zapatos ligeros Athletic Sneaker de Roma Azul oscuro I Zapatillas adidas Outdoor Terrex Agravic para mujer Sin teñir / Blanco / Aero Verde Teva Alp - Mujeres Helecho Zapatillas de running Brooks Womens Ghost 10 Neutral acolchadas Azul marino / rosa / verde azulado Zapatillas para correr Nike Women s Free Rn Flyknit 2017 Solar Rojo / Negro / Mango Zapatillas de running Altra AFW1837F para mujer Torin 3.5 Rosado , Sandalias de mujer Merrell, Sandspur Rose Cacao Zapatillas para caminar Ww840v2 New Balance para mujer Gris Sandalia adidas Duramo Slide Negro / Blanco / Negro , Sperry Womens Fathom Negro Zapatillas Skechers para mujer Go Walk Cool-15651 Sneaker Carbón de leña / Turquesa STEVEN by Steve Madden Zapatillas de mujer NC-Slate para caminar Oro rosa , Zapato de skate Chelsea Se de mujer DC Negro / Plata / Negro ASICS Tiger Gel-Lyte V Sanze TR Meerkat / Meerkat , Diadora B. Original Sneaker para hombre Negro / gris FootJoy EmPower BOA Zapatos de golf CERRAR Mujeres Plata / Lila, Plata , Sandalias Jerusalem Sandalia Joanna para mujer rojo Mizuno 9-Spike Swift 3 Switch Softball Cleat Azul marino / blanco Baabuk Gus Slipper Violeta claro , Bed | Stu Botines para mujer estridentes Tinte Di Moro Dip Dye , Botín de tobillo Landrue para mujer de la marca Lucky Negro , Zapatilla Zumaia Nf45 para mujer El Naturalista Grosella Mixta , Botas de invierno Big Spender para mujeres no calificadas Negro

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 Negro running New Balance New 990V3 990V3 para mujer Negro ac56879 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