Posted on March 14, 2015September 18, 2018 by Kirk Weiler

Happy Pi Day – Desmos Graphers

I hope that everyone is sufficiently celebrating the Pi Day of the century. If you missed the morning celebration, then set your alarms for 9:26 pm tonight (preferably at 53 seconds).

In celebration, I thought I would post two of my favorite Desmos graphs based on the sublimely elegant geometry of the circle. The first, Spirograph, I posted once before.

Just hit play on the “a” button and watch the smaller circle move within the larger one to trace out a classic spirograph curve. Experiment by changing the sizes of the two circles. Don’t be scared to make the outer circle smaller than the inner circle.

The second circle based Desmos graph is my complex Ferris wheel. We’ll be doing this project soon in my Math 4 Honors class and I’m super excited about it. Here’s the Desmos graph for the Ferris wheel:

Desmos Complex Ferris Wheel

Hit play on the “a” button to watch the Ferris wheel in motion. If you want to see the curve traced out, activate the equation in row 2 by clicking on its open circle. Play around by modifying the values of the two radii involved in the problem. Also, try varying the periods of the two rotations.

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