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walks around or across an equilateral (2019 Novosibirsk Oral Geo Oly 7.2)

Source:

April 26, 2021
geometrydistanceEquilateral

Problem Statement

Kikoriki live on the shores of a pond in the form of an equilateral triangle with a side of 600600 m, Krash and Wally live on the same shore, 300300 m from each other. In summer, Dokko to Krash walk 900900 m, and Wally to Rosa - also 900900 m. Prove that in winter, when the pond freezes and it will be possible to walk directly on the ice, Dokko will walk as many meters to Krash as Wally to Rosa.
[url=https://en.wikipedia.org/wiki/Kikoriki]about Kikoriki/GoGoRiki / Smeshariki