Answer:
The answer is explained below
Explanation:
Statement Reason
Triangle ACD is isosceles and Given
<1 = <3 (<1 is congruent to <3)
∠3 = ∠4 Isosceles triangle base angles.
∠1 = ∠4 Substitution Theorem
∠1 = ∠4 They are produced by two lines . AB and CD cut by transversal
. line AD
Segment AB || Segment CD Alternate interior angle theorem
The Alternate interior angle theorem states that if two lines cut by a transversal line form congruent alternate interior angles, then the two lines are parallel to each other.