Section Euclid.
Context `{Ax:area}.

Lemma proposition_43 :
forall A B C D E F G H K,
PG A B C D -> BetS A H D -> BetS A E B -> BetS D F C -> BetS B G C -> BetS A K C -> PG E A H K -> PG G K F C ->
EF K G B E D F K H.