Problem 6 · 2016 Math Kangaroo
Medium
Spatial & Visual Reasoning
spatial-reasoning
What is the minimum number of planes necessary to border a certain region in three-dimensional space?
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Answer: B — 4
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Hint 1 of 2
What is the simplest bounded solid?
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Hint 2 of 2
A tetrahedron is bounded by the fewest flat faces.
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Approach: simplest bounded polyhedron
- A region bounded by planes is a polyhedron; the one with the fewest faces is the tetrahedron.
- A tetrahedron has 4 faces, and no bounded region can be made with only 3 planes.
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