In the triangle congruence rule ASA, what does 'A' represent?

In the triangle congruence rule ASA, the letter 'A' represents an Angle. Specifically, ASA stands for Angle-Side-Angle, which is a criterion used to determine whether two triangles are congruent. For two triangles to be congruent with the ASA criteria, two angles and the included side must correspondingly match.

Congruence in geometry means that the triangles have exactly the same shape and size, which can be established when two angles of one triangle are equal to two angles of another triangle, along with the side between those angles being equal as well. This rule is powerful because it allows for the conclusion of congruence without needing to know all sides of the triangles, focusing instead on their angles. Thus, defining 'A' as angle is essential to understanding the ASA congruence criterion.