Geometry Problems, Online Education


Geometry Problem 41: Sangaku, Mickey Mouse, Three Circles, Tangent, Radii, Chord, Tangency Points, Metric Relations


The figure shows three circles (representing head and ears of Mickey Mouse) where a, b and c are respective radii, and d is the length of the exterior tangent. Prove that: .

Sangaku Mickey Mouse Geometry Problem

Flyer of problem 41 using iPad Apps

Flyer of problem 41 using iPad App

Sketch and Typography of Problem 41

Sangaku Problem 41 Circle, Tangent, Measurement, Sketch and Typography

See also:
Problem art 41
Sketch art of problem 41

References: Fukagawa Hidetoshi, Tony Rothman, "Sacred Mathematics: Japanese Temple Geometry" (Princenton University Press, 2008).

Sangaku or San Gaku
are Japanese geometrical problems in Euclidean geometry on wooden tablets created during the Edo period (1603-1867) by members of all social classes.

I have used Geometry Expressions to visualize these geometric forms and check out a variety of conjectures. Geometry Expressions is the world's first Interactive Symbolic Geometry System. This means: Geometric figures can be defined by either Symbolic Constraints or numeric locations.

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Last updated: Sep 4, 2014

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