It was created for the use of congruence between segments,
angles, and triangles. Also it was created for the transitional
property of congruence, symmetry property of congruence, and
Reflexive property of congruence.
Congruence is basically the same as equality, just in a
Reflexive Property of Congruence: AB =~ AB
Symmetric Property of Congruence: angle P =~ angle Q, then angle
Q =~ angle P
Transitive Property of Congruence: If A =~ B and B =~ C, then A
When in a triangle, for angle A, B, C; As the symmetric property
of congruence , when ∠A ≌ ∠B then ∠B ≌ ∠A and when ∠A ≌ ∠C then ∠C
≌ ∠A and when ∠C ≌ ∠B then ∠B ≌ ∠C
This is the definition of symmetric property of congruence.