Answer:
Transitive property
Step-by-step explanation:
Given
See attachment
Required
The missing property?
In step 1, we have:
[tex]\angle A \cong \angle B,\ \angle C \cong \angle B[/tex]
Transitive property states that:
If [tex]a = b[/tex] and [tex]b = c[/tex]
Then [tex]a = c[/tex]
Similarly:
If [tex]\angle A \cong \angle B[/tex] and [tex]\angle C \cong \angle B[/tex]
Then [tex]\angle A \cong \angle C[/tex] --- step 3
Hence, we can conclude that the transitive property is the missing justification
