Answer:
Transitive property is used in step 4.
Step-by-step explanation:
Transitive property states that if
[tex]a = b \\b = c\\ then\\a = c[/tex]
Here we have
[tex]\angle 5 \cong \angle 1\\\angle 1 \cong \angle 3\\then\\\angle 3 \cong \angle 5[/tex]
