Apr 112015
 

DailyMinimal ant triangle

Here’s a website showcasing minimalist geometric shapes and patterns. I find myself looking at many of these and seeing a lot of relationships that are not immediately apparent. Also it’s nice to think of extensions that could become GeoGebra apps, which would generalize/customize these nicely done images. Daily Minimal, http://www.dailyminimal.com/, is hosted by (in the author’s own words) “I’m a 19 years old Paris based graphic designer and student in chemistry. DAILY MINIMAL is an art blog dedicated to minimalism and geometry. My main goal is to show all possibilities provided by the geometry by publishing a new project each day. I find my inspiration in science, nature, and the most common things of the life.”

 

Pi Day Pics

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Mar 102015
 
Here’s a great set of pictures for math teachers and other pi fans, found at NETWORKWORLDPi plate wikipedia
This year Pi Day is special, because it happens on 3/14/15, and the decimal representation of pi is 3.1415 . . .
Some folks are calling it Pi Day of the Century – we’ll see.
Dec 292014
 

This is a great exercise for Common Core Geometry instruction in the area of transformations.

HINT: highlight a slider’s button, then use your cursor keys for fine adjustment; play around with the numbers to get pleasing shapes.

Use slider n for number of iterations
Use slider r for rotation in 0.001 increments
Use slider d for dilation in 0.001 increments
Build command structure in 3 steps:
Enter Dilate[poly1, d^i], where i = 1, 2, 3 to find pattern
Enter Rotate[Dilate[poly1, d^i], i r π], where i = 1, 2, 3 to find pattern
Enter Sequence[Rotate[Dilate[poly1, d^i], i r π], i, 1, n, 1]
This Sequence command should work for all polygons.

The downloadable file can be found here.

My other GeoGebraTube apps can be found here.

Dec 292014
 

Number of diagonals in a polygon:
If n = number of vertex points, then D = number of diagonals = n(n-3)/2.
Slider n controls the number as well as the color. In the Advanced tab,
Red = n / 36, Green = 1 – n / 36, and Blue = 0, so the color changes from Green
to Red as the number of sides moves from 3 to 36.
reference: I modified sonom’s idea from http://tube.geogebra.org/material/show/id/137056

The downloadable file can be found here.

My other GeoGebraTube apps can be found here.

Dec 292014
 

An epitrochoid is the path traced by a point on a circle (M)
that travels on the outside of another circle (E).
This can be used to model the path of the Moon (M) in orbit around the Earth (E).
There are about 13.3 revolutions(n) of the Moon about the Earth in one year.
-credit-Malin Christersson-http://www.geogebratube.org/material/show/id/87141

The downloadable file can be found here.

My other GeoGebraTube apps can be found here.