Problem 7 · 2024 Math Kangaroo
Medium
Spatial & Visual Reasoning
foldingreflection
Manuel has a round transparent piece of paper with some circles on it (see diagram on the right). He folds it along the dashed line. What does it look like once it has been folded?
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Answer: C
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Hint 1 of 2
Folding along the dashed line flips the left half onto the right half like a mirror.
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Hint 2 of 2
The folded picture shows the right-hand circles plus the mirror images of the left-hand circles laid on top.
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Approach: reflect the left half over the fold line and overlay
- The fold is a reflection across the dashed line.
- Each circle on the folded-over half lands at its mirror position on the other half.
- Combine the fixed circles with these reflected circles to see the result.
- The matching picture is C.
Mark:
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