A non-convex n-gon was cut by a straight-line cut into three parts, after which two of the parts were assembled into a polygon equal to the third part. Can n be a) 5?
b) 4?
This one wants a proof. Work it on paper, read the official solution, then mark
yourself honestly — the ladder only means something if the record is true.
Official solution
See figures a, b.
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Fig. a
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Fig. b
## Answer
a), b) Yes.
Source: NuminaMath-1.5,
licensed Apache-2.0.
Statement and solution reproduced as published; topic, difficulty and ordering added
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