EXPLANATION
The statements and reasons will be as shown as follows:
Statement Reason
< 10=<14 Given
< 14=<12 Vertical angles are congruent
< 10=<12 Transitive property
s//t Converse of corresponding angles Theorem
Converse of corresponding angles Theorem: If the corresponding angles formed by two lines and a transversal are congruent, then the lines are parallel.