Answer:
Definition of Congruent angles.
Explanation:
Given
See attachment
Required
Complete the proof at step 8
At step 8, we have:
![\angle ABC \cong \angle ABD](https://img.qammunity.org/2022/formulas/mathematics/high-school/kusocw8a0n4gi0b6c5hrm4namlv3bu4l8v.png)
When the sign
is used, it means congruence
In other words;
ABC and ABD are congruent
Hence, the missing statement at step 8 is: Definition of Congruent angles.