MathDB

4

Part of 2003 Czech-Polish-Slovak Match

Problems(1)

If the resulting quad is cyclic, then ABC must be isosceles

Source: Czech-Polish-Slovak 2003 Q4

4/28/2013
Point PP lies on the median from vertex CC of a triangle ABCABC. Line APAP meets BCBC at XX, and line BPBP meets ACAC at YY . Prove that if quadrilateral ABXYABXY is cyclic, then triangle ABCABC is isosceles.
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