There are markings given in the diagram.
(Angle) ∠A and ∠D are =
(Side) AC and DB are =
(Side) In a trapezium, the opposite sides are equivalent, meaning AB and DC are =
So you got side, angle, and another side.
You can form the SAS (Side-Angle-Side) similarity theorem.
You can also use the reasons above to make a Statement-Proof table
