Stage: 5 Challenge Level: 
A and B are the centres of two opposite faces of a regular solid dodecahedron.
What is the shortest distance between A and B on the surface?
Index notation/Indices. Dodecahedra. Circles. Sine. Cosine. Complex numbers. Quadratic equations. Regular polygons. Long problems. Pythagoras' theorem.
Published November 1997.
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