Advanced Geometric Problem & Solution (Twice a week update) Now 4742 problems posted.
<Qua-2026-807>, hint
Since <PCQ=<PDQ, <PAQ=<PBQ
PCDQ PBAQ are cyclic , Hence <PCD=<PQA, <PQA+<PBA=180, AB//CD
<Qua-2026-807>, cyclic, parallel
<Singapore Senior Math Olympiad 2018>
<Qua-2026-806>, hint
<Qua-2026-806>,cyclic, midpoint
<Singapore Senior Math Olympiad 2017>
<Tri-2026-2299 >,hint
Line BP cut AC at B' and line MP cut AB at M'.
Then APB and APB' are congruent and BP=PB'
since M is the midpoint of BC, line MP//AC and cut AB at midpoint M'
By Ceva's theorem (AM'/M'B)x(BD/DM)x(MQ/QA)=1
Since AM'=M'B, BD/DM=AQ/QM, Hence DQ//AB.