Section CONGRUENT_TRIANGLES.
Definition CongruentTriangles (A B C A' B' C' : Point) :=
Distance A B = Distance A' B' /\
Distance B C = Distance  B' C' /\
Distance C A = Distance C' A'.

Lemma CongruentTrianglesSASB : forall A B C A' B' C' : Point,
Distance B A = Distance B' A' ->
Distance B C = Distance  B' C' ->
Angle A B C = Angle A' B' C' ->
B <> A ->
B <> C ->
CongruentTriangles A B C A' B' C'.