Question

What is the missing justification?

Answer 1

Answer:

Transitive property

Step-by-step explanation:

Given

See attachment

Required

The missing property?

In step 1, we have:

$\angle A \cong \angle B,\ \angle C \cong \angle B$

Transitive property states that:

If $a = b$ and $b = c$

Then $a = c$

Similarly:

If $\angle A \cong \angle B$ and $\angle C \cong \angle B$

Then  $\angle A \cong \angle C$ --- step 3

Hence, we can conclude that the transitive property is the missing justification