Write a two-column proof. Given: Triangle ACD is isosceles; <1 is congruent to <3 Prove: Segment AB || Segment CD

Answer:
AB ║ CD, reason If two lines (AB and CD) and a transversal AD, form alternate interior angles, (∠1 and ∠4) that are congruent, then the two lines are parallel
Step-by-step explanation:
Statement, Reason
Triangle ACD is isosceles, Given
∠1 ≅ ∠3, Given
∠3 ≅ ∠4, Base angles of isosceles triangle
∠1 ≅ ∠4, Substitution
∠1 and ∠4, are alt int. ∠s, Definition
AB ║ CD, Have congruent alternate interior angles
If two lines (AB and CD) and a transversal AD, form alternate interior angles, (∠1 and ∠4) that are congruent, then the two lines are parallel
The two-column proof that shows that Segment AB║Segment CD is shown in the image attached below (See attachment).
Given the image showing an isosceles triangle, ΔACD.
The two-column proof that shows segment AB || Segment CD has been provided in the table shown in the image attached below.
We know already that:
ΔACD is isosceles
∠1 ≅ ∠3
∠3 and ∠4 base angles of the isosceles triangle, therefore, ∠3 ≅ ∠4.
By substitution, ∠1 ≅ ∠4
∠1 and ∠4 are alternate interior angles, therefore, based on the Converse of Alternate Interior Angles Theorem: AB║CD
The complete two-column proof is in the image attached below.
Learn more about Alternate Interior Angles Theorem on:
https://brainly.com/question/19486848