Discussion: Other students submitted incorrect solutions to this problem - they went along an edge of one face and then the diagonal of the other. Cleverly this student opens up the cube as if it is made of cardboard and makes it into a plane surface and uses the fact that the shortest distance between two points is a straight line and the Pythagorean theorem to solve the problem. This is a good example of lateral thinking or not being trapped or looking for an alternative representation.
Written response: Great insight: unfold the cube so that the surface lies in a plane so that he shortest distance is a straight line joining the points. This is a good example of "look at the problem in a different way."
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