Problem 24 · 2017 Math Kangaroo
Stretch
Spatial & Visual Reasoning
reflectiontiling-tessellation
The first kangaroo is repeatedly mirrored (reflected) across the dotted lines. Two reflections have already been carried out. In which position is the kangaroo in the grey triangle?
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Answer: E
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Hint 1 of 2
Each step flips the kangaroo across the next dotted edge; reflecting twice restores orientation but moves it.
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Hint 2 of 2
Track the kangaroo through the reflections into the grey triangle and read off its pose.
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Approach: apply successive reflections across the triangle edges
- Reflecting across each shared dotted edge flips the kangaroo's orientation in alternating triangles.
- Carry the flips along the strip until reaching the grey triangle.
- The resulting pose matches option (E).
- So the kangaroo in the grey triangle looks like (E).
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