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MathNet 2023-part-05 — 191 problems (EN–VI) Question 29

Math Olympiad Vault · MathNet 2023-part-05 — 191 problems (EN–VI)

Question 29

Let $M$ be the midpoint of the side $CD$ of the square $ABCD$. The perpendicular from $C$ onto $BM$ meets the lines $BM$ at $N$, and $AB$ at $E$. The line $BM$ intersects the line $AD$ in $P$. Let $F$ be the midpoint of the segment $BN$. Prove that:

a) the triangles $CBE$ and $BAP$ are congruent;

b) the segments $AN$ and $DF$ are congruent and perpendicular.