Symmetric property of congruence.
Solution:
Given statement:
If ∠1 ≅ ∠2, then ∠2 ≅ ∠1.
To identify the property used in the above statement:
Let us first know some property of congruence:
Reflexive property:
The geometric figure is congruent to itself.
That is [tex]\overline{A B} \cong \overline{A B} \text { or } \angle B \cong \angle B[/tex].
Symmetric property of congruence:
If the geometric figure A is congruent to figure B, then figure B is also congruent to figure A.
That is [tex]\overline{A B} \cong \overline{C D}, \text { then } \overline{C D} \cong \overline{A B}[/tex].
Transitive property of congruence:
If figure A is congruent to figure B and figure B is congruent to figure C, then figure A is congruent to figure C.
That is [tex]\angle A\cong \angle B, \ \angle B\cong \angle C \ \text{then} \ \angle A\cong \angle C[/tex]
From the above properties, it is clear that,
If ∠1 ≅ ∠2 then ∠2 ≅ ∠1 is symmetric property of congruence.
