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2024 Math Kangaroo

Problem 1

Problem 1 · 2024 Math Kangaroo Easy
Spatial & Visual Reasoning path-tracing

The diagram on the right is made up of five-sided tiles of equal size. Which tile can be inserted in the missing spot so that two closed lines are formed?

Figure for Math Kangaroo 2024 Problem 1
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Answer: C
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Hint 1 of 2
The grid in the corner already has lines running into the empty slot; the inserted tile must continue them.
Still stuck? Show hint 2 →
Hint 2 of 2
You need the two arcs in the hole to join up into exactly two separate closed loops, so match where each line meets the tile's edges.
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Approach: match the line endpoints so the curves close into two loops
  1. Look at where the existing curves hit the boundary of the missing pentagon-shaped slot.
  2. The added tile must have its two arcs touch those same edge points so the strokes connect.
  3. Only the tile whose arcs link the open ends into two complete closed lines works.
  4. That tile is C.
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