Answer:
Explanation:
Part A.
Angles with measures
and
are alternate interior angles when two parallel lines are cut by a transversal. By Alternate Interior Angles theorem,

Part B.
Angles a and
are congruent as vertical angles, so

Angles
and d are the same side interior angles, so the add up to 180°, thus

Angles d and f are congruent as vertical angles.
Angles e and
are congruent as vertical angles.
Angles c and d are congruent as alternate interior angles.
Angles c and b are congruent as vertical angles.
Therefore,