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MathNet 2022-part-01 — 197 problems (EN–VI) Question 78

Math Olympiad Vault · MathNet 2022-part-01 — 197 problems (EN–VI)

Question 78

Three non-intersecting circles of radius $1$ are placed inside the triangle $ABC$. (Circles can touch each other and the sides of a triangle, but cannot share interior points.)
Find the largest value of $r$ for which we can be sure that inside the triangle it is possible to draw a fourth circle of radius $r$ that doesn't intersect with three circles already drawn.