All the steps I added have red numbers. The things I changed are in red as well.
Statements:
1. ;
2. ;
3.
4.
5.
6.
Reasoning:
1. Given
2. Angle addition postulate
3. Transitive property (or Substitution)
4. Transitive Property (or Substitution)
5. Substitution
6. Subtraction property of equality