Answer:
Alternative interior angle theorem states that when two parallel lines are crossed by transversal line, then the pairs of angles on the inner side each of those two lines but on opposite sides of the transversal are equal.
Given: TUVW is an isosceles trapezoid with TU parallel to WV.
In triangle TXU and triangle VXW.
By alternative interior angle theorem;
[Angle]
[Angle]
AA(Angle-Angle) similar theorem states that the two triangles are similar if they have two corresponding angles that are equal.
then, by AA-similarity theorem;

Therefore, a triangle TXU and triangle VXW are similar triangles.