Congruence

Mathematics — Second Preparatory

Common mistakes

Writing the congruence with the vertices in a non-matching order. For example, Δ ABC ≅ Δ FED is wrong when the correct order is Δ ABC ≅ Δ DEF.
Using two sides and an angle that is not between them to prove congruence.
Assuming that equal angles alone prove congruence. Such triangles may be similar but not congruent.
Forgetting that corresponding sides lie opposite the corresponding angles.

Congruence · 4 / 5