Congruence refers to the state of two shapes or figures being identical in form and size. In geometry, this means that if one shape can be transformed into another through rotation, reflection, or translation, they are considered congruent. For example, two triangles are congruent if their corresponding sides and angles are equal. In mathematics, congruence can also apply to numbers, particularly in modular arithmetic. Two integers are congruent modulo a number if they leave the same remainder when divided by that number. For instance, 7 and 3 are congruent modulo 4 because both leave a remainder of 3 when divided by 4.