Problem 15 · 2019 Math Kangaroo
Medium
Spatial & Visual Reasoning
paper-cuttingfolding
Bridget folds a square piece of paper in half, then in half again, and then cuts it along the two lines shown in the picture. How many pieces of paper does she get?
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Answer: C — 9
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Hint 1 of 3
Folding the square in half twice stacks it into four layers.
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Hint 2 of 3
One snip through four layers makes four cuts at once, so imagine the cut lines reflected when you unfold.
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Hint 3 of 3
Draw the unfolded square with all the cut lines and count the separate pieces.
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Approach: track the cuts through the folded layers, then unfold
- Folding the square twice stacks it into four layers.
- The two cuts slice through all the layers; unfolding turns each cut into a full line across the paper.
- Counting the regions those lines make gives 9 separate pieces (C).
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