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Join AO in the first diagram. What is the angle between AO and the red fold line? Now find angle REO.
We are given a regular icosahedron having three red vertices. Show that it has a vertex that has at least two red neighbours.
Glarsynost lives on a planet whose shape is that of a perfect regular dodecahedron. Can you describe the shortest journey she can make to ensure that she will see every part of the planet?