Problem

Source: Lithuanian TST 2014

Tags: geometry, ratio



Circles ω1 and ω2 have no common point. Where is outerior tangents a and b, interior tangent c. Lines a, b and c touches circle ω1 respectively on points A1, B1 and C1, and circle ω2 – respectively on points A2, B2 and C2. Prove that triangles A1B1C1 and A2B2C2 area ratio is the same as ratio of ω1 and ω2 radii.


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