Require Export GeoCoq.Elements.OriginalProofs.proposition_42.
Require Export GeoCoq.Elements.OriginalProofs.lemma_samesideflip.
Section Euclid.
Context `{Ax:area}.

(* Specifications: *)
Lemma proposition_42B :
forall B C D E J K R a b c e,
Triangle a b c -> Midpoint b e c -> nCol J D K -> Midpoint B E C -> Cong E C e c -> nCol R E C ->
exists X Z, PG X E C Z /\ EF a b e c X E C Z /\ CongA C E X J D K /\ OS R X E C.