Problem 16 · 2019 Math Kangaroo
Medium
Spatial & Visual Reasoning
net-folding
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Answer: D
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Hint 1 of 3
Imagine folding each net into a cube and watch where the drawn line sits on each face.
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Hint 2 of 3
When two faces meet at an edge, the line ends on that edge join up.
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Hint 3 of 3
A closed loop means every end of the line meets another end, with no loose ends left over.
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Approach: fold each net and check the line ends meet
- When a net folds into a cube, edges that touch bring the line segments' ends together.
- For a closed loop, every end of the drawn line must meet another end with no loose ends left.
- Only net D closes up into a single loop (D).
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