The theorem that justifies this statement ∠4≅∠6 is; Alternate Interior Angles.
What are Alternate Interior angles?
When two parallel lines are crossed by a transversal line, the pair of angles formed on the inner side of the parallel lines, but on the opposite sides of the transversal are called alternate interior angles. These alternate interior angles are always equal.
From the given diagram, we see that ∠4 and ∠6 fall into the category of alternate interior angles.
Read more about Alternate Interior angles at; https://brainly.com/question/24839702
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