The symbol '≅' indicates that two geometric figures are congruent, meaning they have the same shape and size.

The order of the vertices in congruence statements matters because it indicates which angles and sides correspond to each other.

We can conclude that corresponding sides and angles of ∆ABC and ∆DEF are equal.

Congruent triangles are triangles that are identical in shape and size, meaning all corresponding sides and angles are equal.

Two triangles are congruent by the SSS (Side-Side-Side) criterion if all three sides of one triangle are equal to the three sides of the other triangle.

The ASA (Angle-Side-Angle) criterion states that if two angles and the included side of one triangle are equal to two angles and the included side of another triangle, then the triangles are congruent.

The included angle in a triangle is the angle formed between two sides of the triangle.

The AAS (Angle-Angle-Side) criterion states that if two angles and a non-included side of one triangle are equal to two angles and the corresponding non-included side of another triangle, then the triangles are congruent.

Congruence means the triangles are the same size and shape, while similarity means the triangles have the same shape but may differ in size.

A corresponding side in congruent triangles is a side that is equal in length to the side of another triangle that is congruent to it.