Euclid's Muse

your source for INTERACTIVE math apps

by Nick Halsey

Circles, Tangents, and Heptagon Diagonals

Two circles are centered at intersection points of diagonals of a regular hepatgon. It turns out that circles centered at intersection points in regular polygons (particularly interestingly with polygons of odd numbers of sides) can be tangent to many other diagonals of that polygon. Try resizing the circles by dragging the green points. How many diagonals can each circle be tangent to? Ready for more? Check out the nonagon version!
by Phil Todd

September Problem

The radii of the small circles add up to that of the large circle. Why?
Welcome to Saltire Software’s app repository: Euclid’s Muse. This site features hundreds of free math apps created by our users. Upload, share and discuss your favorite apps created with Geometry Expressions. Join today and add to the collection.

News

Updates to Euclid’s Muse

We are excited to announce some of the recent updates to Euclid’s Muse. The front page has been reorganized so it’s easier to find what you’re looking for (and it’s much nicer to look at). Join us on the new forums page and help build our community by posting your questions, comments and app creation […]

Announcing Mechanical Expressions!

We’ve just released a new program, Mechanical Expressions. It builds off of Geometry Expressions’ base, adding mechanics inputs and outputs. Its html5/Javascript app exports support dynamic simulations, so keep your eyes open for some popping up here on Euclid’s Muse. For more information about Mechanical Expressions, check out the website: http://mechanicalexpressions.com/.

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