MathDB

15

Part of 2005 Baltic Way

Problems(1)

Prove that XY passes through H

Source: Baltic Way 2005

12/28/2010
Let the lines ee and ff be perpendicular and intersect each other at HH. Let AA and BB lie on ee and CC and DD lie on ff, such that all five points A,B,C,DA,B,C,D and HH are distinct. Let the lines bb and dd pass through BB and DD respectively, perpendicularly to ACAC; let the lines aa and cc pass through AA and CC respectively, perpendicularly to BDBD. Let aa and bb intersect at XX and cc and dd intersect at YY. Prove that XYXY passes through HH.
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