Answer:
Explanation:
This is not a valid proof, as it simply repeats the given statement without providing any justification or reasoning. To prove that AB CD, we need to use logical reasoning and the properties of lines and angles to show that the statement is true.
One way to prove this statement is to consider the angles of the quadrilateral ZBZD. Since ZBZD is a quadrilateral, it has four angles. We are given that ZB is parallel to AD and that BC is parallel to AD. This means that the angles formed by these lines must be equal.
Additionally, since ZBZD is a quadrilateral, the sum of its angles must be 360 degrees. Therefore, if the angles formed by ZB and AD are equal, and the angles formed by BC and AD are equal, then the angles formed by ZB and BC must also be equal.
Therefore, we can conclude that ZB and BC are parallel, which means that AB CD. This completes the proof.